Apple A8 vs Snapdragon 805 vs Exynos 5433 - Smartphone SoC Comparison (2014 Edition)

Smartphones have become just about the most important gadget in a person's life, since it has positioned itself as a sort of a does-everything device (recently, even measuring your heart rate). As such, it needs a powerful processor to keep things going smoothly, even with so many utilities and features baked in. Accordingly, smartphone processor performance has seen exponential growth over the last few years, blazing past even some older laptops at this point. This year of 2014 we have the latest and greatest ultra-mobile processors shipping in devices in time for the holiday season. Among the best competitors we have: Apple, with its A8 processor, found in the iPhone 6 and 6 Plus, Qualcomm, with its latest and greatest Snapdragon 805, and Samsung's Octa-core Exynos 5433 SoC. It's no doubt that all three processors are performance monsters, but which of them offers the best performance, and more importantly, which one is the most power efficient?

Firstly, let's see how these processors compare on paper:

	Apple A8	Snapdragon 805	Exynos 5433
Process Node	20nm	28nm HPM	20nm HKMG
CPU	Dual-core 64-bit "Enhanced Cyclone" @ 1.4GHz	Quad-core 32-bit Krait 450 @ 2.7GHz	Octa-core 64-bit big.LITTLE (Quad-core ARM Cortex-A57 @ 1.9GHz + Quad-core ARM Cortex-A53 @ 1.3GHz)
GPU	PowerVR GX6450 @ 450MHz (115.2 GFLOPS)	Adreno 420 @ 600MHz (337.5 GFLOPS)	Mali T760-MP6 @ 700MHz (204 GFLOPS)
Memory Interface	Single-channel 64-bit LPDDR3-1600 (12.8GB/s)	64-bit Dual-channel LPDDR3-1600 (25.6GB/s)	32-bit Dual-channel LPDDR3-1650 (13.2GB/s)

At least on paper, all three processors are extremely powerful and very competitive when it comes to power and efficiency. However, the three SoCs use extremely different approaches to achieve their performance. While Apple prefers to have a smaller CPU core count, whilst making the core itself very large to achieve a high performance with just two cores, Samsung's quantity-over-quality philosophy means that they chose to throw in a very large number of CPU cores (in fact, eight of them). Qualcomm sits between Apple and Samsung, offering four CPU cores with decent per-core performance. In practice, given that most applications do not scale performace very well beyond two cores, I personally prefer Apple's approach, however a more limited selection of apps that can actually utilize a large core count, for instance, games which involve more complex physics calculations, might see Samsung's approach as the fastest option. Either way, the most accurate way of comparing the performance of these processors is using synthetic benchmarks.

Let's start with the GeekBench 3 benchmark, which tests CPU performance:

As you can see, Apple's second generation Cyclone core is just about the fastest core used in any current smartphone. Nvidia's Denver CPU core used in their Tegra K1 SoC outperforms the Cyclone core, but since the Tegra K1 is pretty much a tablet-only platform, I'm not considering it in this comparison. Meanwhile, The also 64-bit Exynos 5433, while behind the A8 by a large margin, is slightly above the Snapdragon 805. I also included data from the Snapdragon 801 chipset to quantify the evolution of the Krait 450 core in the Snapdragon 805 compared to its predecessor, Krait 400. The difference isn't big, actually, which makes for the fact that the Snapdragon 805 has the weakest single-threaded performance of all current high-end SoCs.

With four high-performance CPU cores aided by another four low-power cores (yes, Samsung managed to make both core clusters work at the same time, unlike with their previous big.LITTLE CPUs), it was obvious from the start that Samsung's processor would come out on top in applications that scale to multiple cores. In fact, the Exynos 5433's multi-threaded performance has a significant advantage over the competition. In second place comes the Snapdragon 805, with a much lower yet still very high score. Again, the multi-threaded test shows only a marginal improvement over the Snapdragon 801. And in last place comes Apple's dual-core A8, which, despite employing a very powerful core solution, simply had too few cores to outperform the competition. Still, it's not far behind the Snapdragon 805, and its score is very respectable indeed. 

Now, moving on to what probably is considered the most important area in SoC performance: graphics. To measure these processors' capability for graphics rendering, we turn to the GFXBench 3.0 test.

It's reasonable to say that the three main competitors in the high-end SoC segment are pretty much on par in terms of their GPUs' OpenGL ES 3.0 performance. However, the PowerVR GX6450 in the iPhone 6 Plus takes the lead, followed closely by the Snapdragon 805's Adreno 420, and in last place is the Mali-T760 in the Exynos 5433, but again, losing by a small margin.

For OpenGL ES 2.0 performance we see the performance gap widen, however the same basic trend can be seen: The Apple A8 takes first place, followed closely by the Snapdragon 805 and a bit further behind we have the Exynos 5433. Also note how, unlike what we've seen in the CPU benchmarks, this time the Snapdragon 805 gets a huge boost compared to its predecessor, the Snapdragon 801.

The ALU test focuses on measuring the GPU's raw compute power, and on this front, Qualcomm seems to be sitting very comfortably, since both the Snapdragon 805 and its sucessor the 801 are far ahead of the Apple A8 and the Exynos 5433 GPUs.

The Fill test depends mostly on the GPU's Render Output Units (ROPs) and on the SoC's memory interface. Given that the Snapdragon 805 has a massive memory interface, comparable to the one on Apple's tablet-primed A8X chip, it naturally had a huge advantage in this test. Meanwhile, the Apple A8 is slightly below the last-gen Snapdragon 801, and the Exynos 5433 comes in last place, but by a small margin.

Power Consumption and Thermal Efficiency

Since these chips are supposed to run inside smartphones, a lot of attention has to be given for the SoC to fulfill two requirements: consume as little power as possible, especially during idle times, and not heat up too much when under strain. I believe that Apple's A8 chip fares best in this department, because apart from being built on a 20nm process, it's Cyclone CPU has proved to be quite efficient in previous appearances. As for Samsung's Exynos 5433, despite being built on 20nm too, I'm not sure that a processor that can have 8 CPU cores running simultaneously can keep itself cool when under strain without thermal throttling. Although at least, in terms of power consumption, idle power should be very low thanks to the low-power Cortex-A7 cores. Finally, it's a bit hard to determine how power efficient Qualcomm's processors are because the company discloses close to nothing about its CPU and GPU architectures. However, it is a proved solution. Krait + Adreno SoC's from Qualcomm can be found on almost every flagship smartphone from 2014, so while it has the disadvantage of still not having moved to 20nm, experience from the past proves that their SoCs and architectures are sufficiently efficient. 

Conclusion

It's a bit hard to determine exactly which processor is the best. Each one of these fares better than the others in at least one area, but each also has its clear weakness.

The Apple A8, using just two, however powerful, CPU cores, not to mention at relatively low clock speeds, can deliver top-notch single-threaded performance, however its low core count hurts its performance amid the quad- and octa-core competition in multi-threaded applications. Also, the PowerVR GX6450 GPU was a good choice, as at least for general gaming it appears to be the fastest solution available on any smartphone. Power consumption should be also pretty low thanks to the 20nm process used and to Apple's and ImgTech's efficient architectures.

The Snapdragon 805 is really more of an evolution of the 801, without any huge changes. For instance, it's the only 32-bit processor being compared here. However, it still manages to deliver excellent performance, building on the success of the outgoing 801. While it's single-threaded performance is a bit disappointing for a 2.5GHz CPU, it does very well in multi-threaded applications, nearing the Exynos 5433's performance. The Adreno 420 GPU also performs extremely well, losing only to the Apple A8 in GFXBench's general gaming tests and absolutely destroying the competition in terms of memory bandwidth and raw compute power. While a move to 20nm would be appreciated, Qualcomm's processors are known for being power efficient, so no problem here. 

Finally, Samsung's Exynos 5433 is really a mixed bag. It's 20nm HKMG process, together with the low-power Cortex-A7 cores, makes way for excellent power efficiency, at least in terms of idle power, and thanks to its huge core count, its multi-threaded performance is ahead of everyone else. It should be noted that, despite the 20nm process, having 8 cores running at full load might introduce the need for thermal throttling, especially in a smartphone chassis.

However, the Mali-T760 GPU employed is slightly behind the competition in terms of general gaming performance, and raw compute power is quite disappointing...thankfully, raw compute power matters little to the vast majority of users. Still, it's an excellent GPU, just not THE best. 

Overall, these are all excellent processors, each one with their respective advantages and disadvantages. It all comes down to what aspects you think is more important to you, for instance, if you value performance in multi-threaded applications, a Exynos 5433-powered device is ideal for that. For an excellent all-around package, which is also a proven solution for smartphones (plus admirable GPU compute power), pick a Snapdragon 805 device. And if you don't mind as much about multi-threaded performance, but want to have the best gaming performance in any smartphone, you can pick one of Apple's A8-powered iDevices. 

Apple A8X vs Tegra K1 vs Snapdragon 805 - Tablet SoC Comprarison (2014 Edition)

In the last few years, ultra-mobile System-on-Chip processors have made unprecedented strides in terms of performance and efficiency, advancing very quickly the standards for mobile performance. One form factor that particularly benefits from the exponential growth of SoC performance are tablets, since their large screens allow for the processors' abilities to be fully utilized. For the holiday season of 2014, we have the latest and greatest of mobile performance shipping inside high-end tablets. Apple has made a whole new SoC just for their iPad Air 2 tablet, which they call the A8X. Nvidia's Tegra K1 processor, which borrows Nvidia's venerable Kepler GPU architecture, has also appeared on a number of new high-end tablets. Finally, we also have the Qualcomm Snapdragon 805 processor found in the Amazon Kindle Fire HDX 8.9" (2014). Unfortunately, most other tablets either use the aging Snapdragon 801 processor, or in the case of Samsung's latest high-end tablets, use an even older Snapdragon 800 processor or the also old Exynos 5420 processor, which debuted with the Note 3 phablet in late 2013. In any case, at the pinnacle of tablet performance, we have the Apple A8X, the Tegra K1 and the Snapdragon 805 battling for the top spot.

	Apple A8X	Nvidia Tegra K1	Snapdragon 805
Process Node	20nm	28nm HPM	28nm HPM
CPU	Tri-core "Enhanced Cyclone" (64-bit) @ 1.5GHz	32-bit: Quad-core ARM Cortex A15 @ 2.3GHz  64-bit: Dual-core Denver @ 2.5GHZ	Quad-core Krait 450 @ 2.5GHz
GPU	PoverVR GXA6850 @ 450MHz (230 GFLOPS)	192-core Kepler GPU @ 852MHz (327 GFLOPS)	Adreno 420 @ 600MHz (172.8 GFLOPS)
Memory Interface	64-bit Dual-channel LPDDR3-1600 (25.6GB/s)	64-bit Dual-channel LPDDR3-1066 (17GB/s)	64-bit Dual-channel LPDDR3-1600 (25.6GB/s)

The CPU

It can certainly be said that all of this year's high-end mobile processors have excellent CPU performance. However, each manufacturer took a different path to reach those high performance demands, and that is what we'll be looking at in this section.

Starting with the A8X's CPU, what we have in hand is Apple's first CPU with more than two CPU cores. This time we have a Tri-core CPU, based on an updated revision of the Apple-designed Cyclone core, which utilizes the ARMv8 ISA and is therefore a 64-bit architecture. Clock speeds remain conservative with Apple's latest CPU, going no further than 1.5GHz. So with three cores at 1.5GHz, how does Apple get performance competitive with quad-core, 2GHz+ offerings from competitors? The answer lies within the Cyclone core.
The Cyclone CPU, now in its second generation, is a very wide core. As it is, it can issue up to 6 instructions per clock. Also, each Cyclone core contains 4 ALUs, as opposed to 2 ALUs/core in Apple's previous CPU architecture, Swift. Also, the reorder buffer has been increased to 192 instructions, in order to avoid memory stalls and to utilize more fully the 6 execution pipelines. In comparison, a Cortex-A15 core can co-issue up to 3 instructions per clock, half as much as Cyclone, and can hold up to 128 instructions in its reorder buffer, only two thirds of the amount that Cyclone's reorder buffer can hold.
By building a very wide CPU architecture, and keeping their CPUs to low core counts and clock speeds, Apple has, in one move, achieved excellent single-threaded performance, far beyond what a Cortex A15 or a Krait core can produce, while at least matching the quad-core competition in multi-threaded processing. I've always said that, due to the fact that CPU instructions tend to have a very threaded nature, CPUs should be way more efficient if they are built emphasizing single-threaded performance, and Apple continues to do the right thing with Cyclone.

The Snapdragon 805 is the last high-end SoC to utilize Qualcomm's own Krait CPU architecture, which was introduced WAY back with the Snapdragon S4. Needless to say, it's still a 32-bit core. The last revision of the Krait architecture is dubbed Krait 450. While Krait 450 carries many improvements compared to the original Krait core, the basic architecture is still the same. Like the Cortex-A15 it's based on, Krait is a 3-wide machine, capable of co-issuing up to 8 instructions at once. In comparison to Cyclone, it's a relatively small core, therefore, it won't be as fast in terms of single threaded performance. Krait 450's tweaked architecture allows it to run at a whopping 2.7GHz, or to be more exact, 2.65GHz. In the case of the Snapdragon 805, we have four of these Krait 450 cores. Qualcomm's signature architecture tweak, which involves putting each core on an individual voltage/frequency controller, allows each core to have a different frequency. That reduces the power consumption of the SoC, and should translate into better battery life. With four cores, and at such a high frequency, the Snapdragon 805's CPU gets very good multi-threaded performance, although the relatively narrow Krait core hurts single-threaded performance very much.

Finally, we have the Tegra K1 and its two different versions. The 32-bit version of the Tegra K1 employs a quad-core Cortex-A15 CPU clocked at up to 2.3GHz, and we've seen a CPU configuration like this in so many SoCs that by this point it's a very well known quantity. The interesting story here is the 64-bit Tegra K1, which uses a dual-core configuration of Nvidia's brand new custom CPU architecture, named Denver. If you don't care much to know about Denver's architecture, you'd better skip this section, because there is A LOT to say about Nvidia's custom CPU.

Denver: The Oddest CPU in SoC history

Denver is Nvidia's first attempt at making a proprietary CPU architecture, and for a first attempt it's actually very good. Some of Nvidia's expertise as a GPU maker has translated into its CPU architecture. For instance, exactly like with Nvidia's GPU architectures, Denver works with VLIW (Very Long Instruction Word) instructions. Basically, this means that the instructions are packed into a 32-bit long "word", and only then are sent into the execution pipelines.

Denver's most peculiar characteristic might be this one: it's an in-order machine, while basically every other high-end mobile CPU has Out-of-Order Execution (OoOE) capabilities. Denver's lack of a dedicated engine that reorders instructions in order to reduce memory stalls and therefore increase the IPC (Instructions Per Clock) should be a huge performance bottleneck. However, Nvidia employs a very interesting (and in my opinion unnecessarily complicated) way of dealing with its in-order architecture.

By not having a hardware OoOE engine built into the CPU, Nvidia has to rely on software tricks to reorder instructions and enhance ILP (Instruction Level Parallelism). Denver is actually not meant to decode ARM instructions most of the time. Rather, Nvidia chose to build a decoder that would run native instructions, optimized for maximum ILP. For this optimization to occur, Nvidia has implemented a Dynamic Code Optimizer (DCO). Basically, the DCO's job is to recognize ARM instructions that are being sent to the CPU frequently, translate it into native instructions and optimize the instruction by reordering parts of the instruction to reduce memory stalls and maximize ILP. For this to work, a small part of the device's internal storage must be reserved to store the optimized instructions.

One implication of this system is that the CPU must be able to decode both native instructions and normal ARM instructions. For this purpose there are two decoders in the CPU block. One huge 7-wide decoder for native instructions generated by the DCO, and a secondary 2-wide decoder for ARM instructions. The difference in size between the two decoders shows how Nvidia expects to have the native instructions being used most of the time. Of course, at the first time that a program is run, and there are no optimized native instructions ready for the native decoder to use, only the ARM decoder would be used until the DCO starts recognizing recurring ARM instructions from the program and optimizes those instructions, from which point onwards that specific instruction would always go through the native decoder. If a program ran the same instructions multiple times (for example, a benchmark program), eventually all of the program's instructions would have a corresponding native optimized instruction stored, and then only the native decoder would be utilized. That would correspond to Denver's peak performance scenario.

While Nvidia's architecture might be a very interesting move, I ask myself if it wouldn't just be easier to build a regular Out-of-Order machine. But still, if it performs well in real life, it doesn't really matter how odd Nvidia's approach was. 

Now, going on to the execution potion of the Denver machine, we see why Denver is the widest mobile CPU in existence. That title was previously held by Cyclone, with its 6 execution pipelines, however, Nvidia went a step ahead and produced a 7-wide machine, capable of co-issuing up to seven instructions at once. That alone should give the Denver core excellent single-threaded performance.

The 64-bit version of the Tegra K1 employs two Denver cores clocked at up to 2.5GHz. That makes it the SoC with the lowest core count among the ones being compared here. While single-threaded performance will most certainly be great, I'm not sure that the dual-core Denver CPU can outrun its triple-core and quad-core opponents.

In order to test that, let's start our synthetic benchmarks evalutation of the CPUs with Geekbench 3.0, which evaluates the CPU both in terms of single-threaded performance and multi-threaded performance.

CPU Benchmarks

In single-threaded applications, Nvidia's custom Denver CPU core takes the first place, followed closely by Apple's enhanced Cyclone core on the Apple A8X. Meanwhile, the older Cortex-A15 and Krait 400 CPU cores are far behind, with the 2.2GHz A15 core in the 32-bit Tegra K1 pulling slightly ahead of the 2.7GHz Krait 450 core in the Snapdragon 805. 

In multi-threaded applications, where all of the CPU's cores can be used, the A8X, with its Triple-core configuration blows past the competition. The dual-core Denver version of the Tegra K1 gets about the same performance as the quad-core Cortex-A15 Tegra K1 variant, with the quad-core Krait 450 coming in last place, but by a very, very small margin. 

Apple's addition of one extra core to the A8X's CPU, together with the fact that Cyclone is a very powerful core, make it easily the fastest CPU in the market for multi-threaded applications. While Nvidia's 64-bit Denver CPU core has some impressive performance, thanks to its wide core architecture, it's core count works against it in the multi-threaded benchmark. It is, in fact, the only dual-core CPU being compared here. Even if it's not as fast as the A8X's CPU, Nvidia's Denver CPU is a beast. Were it in a quad-core configuration, it would absolutely blow the competition out of the water.

The GPU

Moving away from CPU benchmarks, we shall now analyze graphics performance, which is probably even more important than CPU performance, given that it is practically a requirement for high-end tablets to act as a decent gaming machine. First we'll look at OpenGL ES 3.0 performance with GFXBench 3.0's Manhattan test, followed by the T-Rex test, which tests OpenGL ES 2.0 performance, followed by some of GFXBench 3.0's low level tests.

The Manhattan test puts the Apple A8X ahead of the competition, followed closely by both Tegra K1 variants, which have about the same performance, since they have the exact same GPU and clock speed. Unfortunately, the Adreno 420 in the Snpadragon 805 is no match for the A8X and the Tegra K1, something that points out the need for Qualcomm to up their GPU game.

The T-Rex test paints a similar picture, with the A8X slightly ahead of the Tegra K1, while both of the Tegra K1 variants get about the same score, and the Snapdragon 805 falls behind the other two processors by a pretty big margin.

The Fill rate test stresses mostly the processor's memory interface and the GPUs TMUs (Texture Mapping Units). Since both the Apple A8X and the Snapdrgon 805 have the same dual-channel 64-bit LPDDR3 memory interface clocked at 800MHz, the performance advantage the Snapdragon 805 has shown in comparison to the A8X can only be attributed to the possibility that the Adreno 420 GPU has better texturing performance than the PowerVX GXA6850 in the Apple A8X. Meanwhile, the two variants of the Tegra K1 feature the same memory interface, which also consists of a dual-channel 64-bit LPDDR3 interface, only with a lower 533MHz clock speed. Therefore, the Tegra K1 offers signifcantly less texturing performance compared to the A8X and the Snapdragon 805, but is a very worthy performer nevertheless.

The ALU test is more about testing the GPUs sheer compute power. Since Nvidia's Tegra K1 has 192 CUDA cores on its GPU, it naturally takes the top spot here, and by a pretty significant margin.

For some reason, all tests show the 32-bit Tegra K1 in the Nvidia Shield Tablet scoring a few more points than the 64-bit Tegra K1 in the Google Nexus 9. But given that the two processors have the exact same GPU, this difference in performance is probably due to software tweaks in the Shield Tablet's operating system, which would make sense, given that it is more than anything a tablet for gaming.

Thermal Efficiency and Power Consumption

In the ultra-mobile space, power consumption and thermals are the biggest limiting factors for peformance. As the three processors being compared here are all performance beasts, several measures had to be taken so that they wouldn't drain a battery too fast or heat up too much.

In order to keep power consumption and die size in check, Apple has decided to shrink the manufacturing process from 28nm to 20nm, a first in the ultra-mobile processor market. That alone gives it a huge advantage over the competition, since they can put more transistors in the same die area, and with the same power consumption. Since the A8X is, in general, the fastest SoC available, the smaller process node is important to keep the iPad Air 2's battery life good. 

Nvidia's Tegra K1 should also do well in terms of power consumption and thermal efficiency in situations where the GPU isn't pushed too hard. The 28nm HPM process it's built upon is nothing particularly good, but it's still not old for a 2014 processor. While the Kepler architecture is very power efficient, straining a 192-core GPU to its maximum is still going to produce a lot of heat in any case. The Nexus 9 tablet reportedly can get very warm on the back while the tablet is running an intensive game.

Finally, the Snapdragon 805 should be the less power hungry processor because it is also a smartphone processor. Given that a 5" phone can carry this processor without heating up too much or draining the battery too fast, a tablet should certainly be able to do the same. To put things in perspective, if we put the Tegra K1 or the Apple A8X inside a smartphone, both would be too power hungry and would produce too much heat to make for a decent phone. In any case, the Snapdragon 805 is, like the Tegra K1, built on a 28nm HPm process. Given that its not as much a performance moster as the other two processors mentioned here, it must be the least power hungry of all three.

Conclusion

Objectively speaking, the comparisons made here make it pretty much clear that once again Apple takes the crown for the best SoC for this generation of high-end tablet processors. Not that the competition is bad. On the contrary, Nvidia went, in just one generation, from being almost irrelevant in the SoC market (let's face it, the Tegra 4 was not an impressive processor) to being at the heels of the current king of this market (aka Apple). The Tegra K1 is an excellent SoC, and even if it can't quite match the Apple A8X, it's still quite close to it in most aspects.

Meanwhile, Qualcomm is seeing it's dominance in the tablet market start to fail. It's latest SoC, the Snapdragon 805, available even on some smartphones and phablets, is available in only one tablet, while most others carry the Snapdragon 801 or even the 800, and this is disappointing, given that a tablet can utilize the processing power more usefully than a smartphone or a phablet. Either way, the Snapdragon 805 is still a very good processor. It's just far from being the fastest. Perhaps Qualcomm should consider, like Nvidia and Apple, making a processor with extra oomph, but meant only to run inside tablets, because while the Snapdragon 805 is an excellent smartphone processor, it's not as competitive in the tablet market. 

Qualcomm's 2014 SoC Lineup: Snapdragon 805, 801, 615, and More

Qualcomm enjoyed a very profitable 2013, with its Snapdragon 400, 600 and 800 System-on-Chips practically dominating the mobile market. And to keep manufacturers interested in Qualcomm's offerings, a refresh of various tiers of the Snapdragon line were recently announced. Specifically, we have six new Snapdragon SoCs coming out this year. 

On the top tier, we have the Snapdragon 801, which will be found inside the Samsung Galaxy S5 and the Sony Xperia Z2 and Xperia Z2 Tablet, as well as the Snapdragon 805, which is even more powerful than the 801, but will be available later this year. On the 600 tier, Qualcomm will offer the Snapdragon 602A, which isn't intended exactly for mobile devices, but rather, it's Qualcomm's offering for in-vehicle infotainment systems. Two 64-bit Snapdragon 600 variants will be available later this year too, the 610, which packs a quad-core CPU, and an octa-core variant named 615. The Snapdragon 410 is also due this year, and it'll pack a 64-bit CPU too.

So you might have noticed that, unlike with last year's Snapdragon lineup, where the designation 200, 400, 600 or 800 made it very clear where each tier stood, this year's numerical designations are a bit of a mess. It's still clear that the 805 and 801 are faster than the 610, 615 and 602A, which in turn are faster than the 410, but there might be some confusion between different variants of the same tier. For instance, 805 could be easily confused for 801, and the same goes for 610 and 615. It's just not as simple to understand as last year's lineup. Not only are the 2014 Snapdragons' nomenclatures messed up, but so are the architectural differences between the new SoCs. You might have noticed that while the 600 and 400 tiers are being upgraded to 64-bit CPU cores, the 801 and 805 are stuck with 32-bit capability, which simply does not make sense. Logically, 64-bit would come to top-tier processors first, and then make its way down to the subsequent tiers, but Qualcomm inexplicably decided to do the contrary. In any case, as it stands, the ability for 64-bit processing still isn't a very important feature in mobile devices, especially since Android OS doesn't even support 64-bit processing.

So let's analize each new Qualcomm SoC one at a time, starting with the high-end.

The Snapdragon 801 processor, found in recently announced Samsung and Sony flagship smartphones and tablets, is merely a mild upgrade over the Snapdragon 800. The biggest change in the 801 is the addition of eMMC 5 support, which will allow for faster flash storage solutions. Other than that, we still have a quad-core Krait 400 CPU, although the clock speed has been ramped up to up to 2.5GHz. This represents an ~8.7% speed increase over the Snapdragon 800. The Snapdragon 801 also keeps the Adreno 330 GPU, but increases its clock speed from 450MHz to up to 578MHz (~28% increase in theoretical performance). The memory interface, while still dual-channel 32-bit DDR3, gets a clock speed increase to 933MHz, which results in 14.9GB/s theoretical memory bandwidth, up from 12.8GB/s in most Snapdragon 800 variants. And that's all. Even though the architecture remains unchanged, the clock speed boosts should give the 801 a considerable performance advantage over the 800. 

Then there's the Snapdragon 805, which will be available later this year and will employ a quad-core configuration of a refresh to the Krait 400 CPU core, the Krait 450. The new CPU's improved efficiency allows for clock speeds to go up to 2.7GHz. Unfortunately, the Krait 450 core is still based on ARMv7, in other words, it doesn't support 64-bit processing. The GPU in the Snapdragon 805 gets a huge uplift, with the new Adreno 420, which brings a DirectX11-class feature set, improves on texture performance, as well as adds dedicated tesselation hardware, something previously seen only on PC graphics cards. The memory interface also gets a huge boost with the Snapdragon 805, moving to a 128-bit wide (quad-channel) LPDDR3-1600 interface. The added interface width results in peak theoretical memory bandwidth of 25.6GB/s. For comparison, most mobile SoCs today top out at 14.9GB/s. 

The Snapdragon 805 doesn't bring any big changes in comparison to the 800, with only mild improvements on the CPU side, but the new, more capable GPU and the impressively wide memory interface are enough to make the Snapdragon 805 an excellent processor. When it's available, I imagine it'll be quite capable to compete with the Tegra K1, the Apple A8 and whatever Samsung has to offer by then.

Moving down to the Snapdragon 600 tier, we have the new Snapdragon 602A which, as stated before, isn't meant for mobile devices, but rather for in-car infortainment systems, an area where many companies, NVIDIA included, have suddenly become interested in. Not much is known about the 602A, but we know it'll have a quad-core Krait (400?) CPU and an Adreno 320 GPU.

The Snapdragon 610 is one of the few Snapdragon processors that support 64-bit processing. It has four ARM Cortex-A53 cores (clock speed unknown) and an Adreno 405 GPU; so far we don't know anything about the GPU, although if it turns out to be a cut-down Adreno 420, we can expect the DirectX11-compatible architecture and the dedicated tesselation hardware. For the record, the Cortex-A53 is the lower end of the two Cortex-A5x CPUs released so far, and it's performance relative to current CPUs is still to be seen.

The Snapdragon 615 is essentially a 610 with four extra CPU cores inside. So it keeps the Adreno 405 GPU, but moves to an octa-core Cortex-A53 CPU. I'm a bit disappointed that Qualcomm decided to increase core count rather than use a more powerful CPU core. Most applications scale better to a fewer amount of threads, so not only will the last four cores or so probably end up not being efficiently utilized, the weaker single-threaded performance of the Cortex-A53 will hurt overall performance in applications that don't scale well to multiple threads. I would've preferred if Qualcomm had used a fewer number of the high-end Cortex-A57 cores, or even used its own Krait cores (even if that meant sacrificing 64-bit processing). 

Finally, there's the Snapdragon 410 mid-to-low-end processor, which combines four 64-bit Cortex-A53 cores at a clock speed of 1.2GHz with an Adreno 306 GPU (since this GPU belongs to the 3xx series, I suspect it won't have the architectural upgrades that the Adreno 405 and 420 got). Not much to go on about here, except to point out that even the weakest Snapdragon processor got an upgrade to 64-bit processing, while the high-end processors didn't. 

While I believe that until mobile processors built on a 22nm process show up there won't be another big leap in SoC performance, I'm not very impressed with Qualcomm's 2014 lineup. The Krait 450 CPU is a very small upgrade compared to the Krait 400, and the excessive use of the Cortex-A53 CPU core in the 600 and 400 tiers is rather disappointing because of the lower-end nature of the Cortex-A53. I'd talk about Qualcomm's decision to give the lower-end processors 64-bit processing, while leaving the high-end stuck at 32-bit, but since it's likely that a) Qualcomm doesn't have a 64-bit successor to Krait yet and b) The Cortex-A57 core is still not available, and since I wouldn't like to have seen more Cortex-A53s on the 800 tier, I won't comment on it. I also might as well reiterate how Qualcomm's nomenclature for its new SoCs can be rather confusing. On the bright side though, at least the Snapdragon 805 is bound to be very competitive, if not industry leading, in terms of GPU performance and memory bandwidth.