In that case why not go for 8 cores for 2/3 of that? Isn't that similar to xbox360, and greater than Wii U? (i may be wrong it's just what Igoogled) Seems plenty for a handheld, but I don't expect a huge 'western AAA' push like some people. Yes Square Enix is talking about DQXI but there's no reason to expect that to be a super cpu heavy game.
It's not a matter of absolute power, but rather getting as close to the NX console as possible within the thermal and die size constraints of a handheld.
Two rules of microprocessor hardware design point to many A53s being the optimal configuration:
- A larger number of smaller cores will in general outperform a smaller number of larger cores at highly parallelisable workloads in the same die area (a straightforward corollary of
Pollack's Rule).
- A larger number of lower-clocked cores will in general outperform a smaller number of higher-clocked cores at highly parallelisable workloads in the same thermal limit (a result of the convexity of power consumption wrt clock speeds).
Videogame logic is becoming increasingly parallelised (as a result of PS4/XBO and PC hardware developments), but isn't fully
embarrassingly parallel, so the question becomes:
"How many hardware threads would developers practically be able to make use of?"
Take your answer to that, add a couple of threads for OS functions, and you have your optimal number of threads X (and in the case of single-threaded cores like we're discussing, cores). Then, take the highest performing cores that would provide X hardware threads in your available die area, and clock them at whatever speeds allow them to fit within your thermal limits.
I would argue that, with developers currently utilising 7 hardware threads on PS4/XBO without great issue, they should be able to make the most out of 10 threads if they were provided them, but more than that may be stretching it. Add two threads for OS duties and you have 12 threads/cores altogether. Twelve A72 cores would obviously be too large for a handheld SoC, but twelve A53 cores should be fine, taking up about 8.13mm² at 14nm
[source]. Assuming 14LPP achieves a 15% reduction in power consumption over 14LPE, and the first graph on
this page is accurate, then a 1W thermal limit for the CPU would allow 1GHz speeds for those 12 A53 cores. (The thermal limit could of course be lower, so for example at 700mW you'd have a clock of 800MHz).