ARM A53/A57/T760 investigated - Samsung Galaxy Note 4 Exynos Review
by Andrei Frumusanu & Ryan Smith on February 10, 2015 7:30 AM ESTConclusion
Samsung's System LSI business had a rough two years as their decision to go with ARM's big.LITTLE SoC architecture cost them a lot of market share, thanks in part to immature software and implementation issues. Usually in the past Samsung's own Exynos SoCs were regarded as the more performant variant given the choice of Qualcomm's Scorpion CPU based solutions. This changed as the Exynos 5410 came out with a malfunctioning CCI, crippling the chip to the most battery inefficient operating mode of big.LITTLE.
Qualcomm's Snapdragon 800 capitalized on the new 28nm HPM manufacturing process, along with the advantage of being able to offer an integrated modem solution, and has dominated the market ever since. It's only now that Samsung is able to recover as the new 20nm manufacturing process allowed them to catch up and start to offer their own Exynos SoC in more variants of its products, a trend that I expect to continue in Samsung's future lineup.
The Note 4 with the Exynos 5433 is the first of a new generation, taking advantage of ARM's new ARMv8 cores. On the CPU side, there's no contest. The A53 and A57 architectures don't hold back in terms of performance, and routinely outperform the Snapdragon 805 by a considerable amount. This gap could even widen as the ecosystem adopts ARMv8 native applications and if Samsung decides to update the phone's software to an AArch64 stack. I still think the A57 is a tad too power hungry in this device, but as long as thermal management is able keep the phone's temperatures in reign, which it seems that it does, there's no real disadvantage to running them at such high clocks. The question is whether efficiency is where it should be. ARM promises that we'll be seeing much improved numbers in the future as licensees get more experience with the IP, something which we're looking forward to test.
On the GPU side, things are not as clear. The Mali T760 made a lot of advancements towards trying to catch up with the Adreno 420 but stopped just short of achieving that, leaving the Qualcomm chip a very small advantage. I still find it surprising that the Mali T760 is able to keep up at all while having only half the available memory bandwidth; things will get interesting once LPDDR4 devices come in the next few months to equalize things again between competing SoCs. Also ARM surprised us with quite a boost of GPU driver efficiency, something I didn't expect and which may have real-world performance implications that we might not see in our synthetic benchmarks.
It's the battery life aspect that I think it's most disappointing to me. It's a pity that Samsung didn't go through more effort to optimize the software stack in this regard. When you are able to take advantage of vertical integration and posses multi-billion dollar semiconductor manufacturing plants with what seem to be talented SoC design teams, it's critical to not skimp out on software. I might be a bit harsh here given that the battery disadvantage was just 12% in our web-browsing test and might be less in real-world usage, and the GPU battery efficiency seems neck-and-neck. Still, it's the wasted potential from a purely technical perspective that is disheartening.
This is definitely a wake-up call to ARM and their partners as well. If the software situation of big.LITTLE isn't improved soon I'm fearing that ship will have sailed away, as both Samsung and Qualcomm are working on their custom ARMv8 cores.
So the question is, is it still worth to try and get an Exynos variant over the Snapdragon one? I definitely think so. In everyday usage the Exynos variant is faster. The small battery disadvantage is more than outweighed by the increased performance of the new ARM cores.
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ddriver - Tuesday, February 10, 2015 - link
I'd like to see A57 performance without being so crippled by a ram bottleneck.blanarahul - Wednesday, February 11, 2015 - link
Loved this article. Only thing missing was gaming fps and power consumption comparison b/w LITTLE cluster only, big cluster only and big.LITTLE modes.ddriver - Thursday, February 12, 2015 - link
Also in true 64bit mode, cuz a lot of the perf improvements in v8 are not available in legacy 32bit mode.It is a shame really, samsung decided the uArch improvements would be enough to barely pass this chip as "incremental", they didn't bother to feed a higher throughput chip with a wider memory bus. As much as it pains me, apple did better in that aspect by not crippling their A7 chip, even if only because they needed it for a "wow factor" after so many generations of mediocre hardware, especially given the many exclusive initial shipment deals they secured to stay relevant.
thegeneral2010 - Wednesday, February 18, 2015 - link
i like wat u say and i really like to see note 4 running on 64bit this would give samsung processors a great push forward and trust of consumers.bigstrudel - Tuesday, February 10, 2015 - link
If it wasn't completely obvious already:Apple A Series stands alone years ahead of the rest of the pack.
Flunk - Tuesday, February 10, 2015 - link
But if they don't sell it to anyone else, it doesn't really matter does it?Apple doesn't compete with Samsung or Qualcomm when it comes to selling SoCs because they don't sell SoCs to other companies. A slight lead in CPU performance is not going to get people to buy an iPhone over and Android, if that's what they're set on buying.
xype - Tuesday, February 10, 2015 - link
It does matter insofar as to be a benchmark of what is possible (as long as they are ahead). And let’s not pretend Apple’s CPUs sucking wouldn’t invite the same kind of comments—just like every situation where 2 competing technologies are compared.Platform/fanboy trolling aside, that’s something Android users benefit from as well. Apple being "stubborn" about 2 core CPUs, for example, is a nice counterweight to the 8 cores and 8 mini-cores and 8 quasi-cores trend that some CPU vendors seem to have a hard-on for, and it gives a nice real-world example of how such an approach to mobile CPU design works out, no?
If Apple stays ahead in the mobile CPU game, the people using non-Apple phones will always have a target to point to and demand equality with. Otherwise they’d just have to live with whatever Qualcomm et al feed them.
bigstrudel - Tuesday, February 10, 2015 - link
My comment isn't fanboy jingo-ism. Its fact.There's not a single Android ARM core on the market that can even match the power of the Apple A7's Cyclone cores much less A8's 2nd gen design.
Were still waiting for anything custom to come out of the Android camp aside from the frankensteinish design of Nvidia's Denver core.
I really shouldn't need to explain why to people on Anandtech.
ergo98 - Tuesday, February 10, 2015 - link
The Tegra K1 64 bit is faster, core per core, versus the A8 (you do realize that the K1-64 has only 2 cores, right? I'm going to have to guess no, or you just are completely unable to read a chart). The A8x offers marginal per core performance advantages over the A8, and the primary benefit is the third core. The K1 64 is a A57 derivative, *exactly like the A8*.Your comments can only be construed as trolling. Can't match the A7? Give me a break.
tipoo - Tuesday, February 10, 2015 - link
Ergo, you're completely off. The Denver K1 is a VLIW code morphing architecture - it has nothing to do with the Cortex A57, nor does the Apple Cyclone, they're both custom architectures.The K1 offers better performance in benchmarks, but as a result of code morphing, it can be hit or miss in real world, causing jank.