There are rumors going around that Qualcomm (QCOM +1.24%) plans to launch a high-end, eight-core, 64-bit Snapdragon 810 system-on-chip later this year for high-end/hero devices. While it is almost assured that Qualcomm will, indeed, build its next-generation processor core around the ARMv8 64-bit instruction set, the rumors that the high-end chip will sport eight cores is highly unlikely.
Mobile devices are all about single-threaded performance
If Qualcomm's goal is to waste a lot of die space and burn up a ton of power at peak performance just to win the artificial benchmark numbers, then perhaps an eight-core high-end chip makes sense. However, Qualcomm didn't become the world leader in smartphone apps processors by making dumb decisions. While this may sound like an unfair derision of the eight-core mobile chip concept, Qualcomm's former CMO Anand Chandrasekher literally said that an "eight-core" mobile CPU was "dumb."
While this individual's remarks about "64-bit" from Apple being a "marketing gimmick" landed him in hot water, his views on eight-core mobile chips is spot-on. The vast majority of client workloads -- smartphone, tablet, PC -- are very dependent on single-core performance. While moving to dual cores does often lead to a tangible benefit in terms of smoothness and overall user experience, quad cores are really pushing it, particularly if per-core performance is sacrificed to get there. Anything beyond that is just wacky.
Apple is the prime example
It is very well known that in mobile CPU-bound tasks, Apple's A7 system-on-chip handily trounces its quad-core competition. This isn't due to the fact that the two cores' performance adds up to something significantly better than the top-end quad-core chips from Qualcomm. Rather, it's because on a per-core basis, Apple's cores are much zippier than Qualcomm's. Only Intel's (INTC +3.01%) Silvermont cores can really trade blows with Apple's. Indeed, here's what respected tech writer Anand Shimpi had to say:
I'm still vetting other SoCs, but so far I haven't come across anyone in the ARM camp that can compete with what Apple has built here. Only Intel is competitive.
NVIDIA is following this trend, too
NVIDIA's (NVDA 0.49%) upcoming Tegra K1 will come in two flavors: a 32-bit version in the first half of 2014 and a 64-bit version in the second half of 2014. The 32-bit K1 will sport a 4-plus-1 configuration, i.e., four ARM Cortex A15 and one low-power A15 built to run at lower power/frequency. But the 64-bit K1 moves to a dual-core configuration with a custom, NVIDIA-built CPU core known as "Project Denver." The core itself is very wide -- and may even be multi-threaded -- and should offer superb single-core performance. That's just what a mobile device needs.
Foolish bottom line
If Qualcomm really goes with an "eight-core" model for its highest-end mobile processor, then it will be time to question the company's design decisions. However, the statements from the former Qualcomm CMO are comforting and tend to suggest that the company is well aware of the silliness of an eight-core mobile processor. The key to mobile performance/smoothness is single-core/single-thread performance, and this is something that Apple, NVIDIA, and Intel seem to understand.
It's a safe bet that Qualcomm understands it, too.
