lopri
Elite Member
- Jul 27, 2002
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Exactly. ARMv8 is a significant reason behind Apple's A7 and A8 performing as well as the Snapdragon 800-series chips of their era (in certain cases, better) despite half the cores and lower clock speeds. Going 64-bit earlier than everyone else just happened to be a nice side benefit.
It sounds like the S810 and Exynos 7 Octa will get a nice boost from ARMv8 and pull ahead of the A8, although that's somewhat expected given that they're coming half a year later.
While I share the thrust of your observation, I take issues with the bolded part: I think we can rise above the misleading hype (largely a creation by Apple and select "journalists" like Anand Lal shimpi who is now an Apple employee). Snapdragons series and A-series SOCs are built from different philosophy, to account for different OS'es needs, and by different financial calculations by different corporations.
I agree that Apple's engineers created a wonderful chip in A7, beating Qualcomm with 64-bit SOC first, and highly refined their architecture in A8 to a degree Qualcomm could not match with theirs. But frankly this recurring theme of "Apple can beat XXXX with fewer cores at lower frequencies" meme needs to die and here is why.
When you compare SOCs, you need to look at the size of the chip, both the single-core performance and multi-core performance, how each architecture better suits target OS, and eventually how large the gap is in perf/watt.
Apple went with highly optimized, fat cores with humongous cache (by mobile standard). Why? I think the No.1 reason is that they believe it to be a better solution for the iOS devices. Whether such an SOC will equally benefit Android is an open question, but I have my doubt. Exhibit No.1: NVIDIA's Denver. It smashes every ARM SOC including A8 in single-core performance. Wonderful, I thought, but why aren't NV following up on it? Instead, they are going with big.LITTLE for their next SOC, Tegra X1. User reviews are mixed on Denver's performance on the Nexus 9. Perhaps the nature of Android (Java VMs, multitask-oriented) makes it better suited for a quad-configuration with medium-sized cores, than an SOC with fat dual-cores?
Also, on balance, S800/S805 and A7/A8 are rather well matched. Similarly sized, similar performance. A7/A8 trump S800/S805 in single-thread performance, but S800/S805 hold slight advantage in multi-core performance and GPU performance. Again, this is not that surprising if you consider what their target products were. And If there is an advantage to A8 in perf/watt, more advanced manufacturing process (20nm v. Snapdragon's 28nm) must have a role there, in addition to Apple engineer's excellent design. I am not trying to diminish what Apple achieved here. Not at all. I just think the misconception spearheaded by an Apple employee (Anand Lal Shimpi) need not be repeated in order to appreciate the excellence of A7/A8 SOCs.
Another point I speculate is not an important one for us - users/enthusiasts/consumers - but there may be financial reasons why it makes more sense for Qualcomm to manufacture quads while Apple can take a risk with duals. Apple make A-series SOCs for themselves, and themselves only. Considering the vertically integrated Apple's business model, and considering iOS products' market position (dominating, that is), Apple can perhaps afford to pay for more expensive, low-yield dies to TSMC. Fat dual-cores face bigger chances of defects assuming no harvesting, and as far as I know there is no die-harvested A8 variant chips. Qualcomm, on the other hand, do not sell consumer products - all they sell are chips. So for them it might make more sense to design smaller cores that are modular, in case of potential low yields and following necessity of die-harvesting.
If you take all these into account, the big picture emerges. Apple created an exceptional chip well suited for their own devices. Qualcomm also make exceptional chips that serve multiple segments of the market. Apple's SOCs may be more sophisticated and a step ahead when it comes to 64-bit adoption, but majority of performance metrics of Apple and Qualcomm's chips are where one might expect them to be within the existing technical boundaries. There is no miracle or a "quantum leap" here.