Daniel Bizo (fejenagy@gmail.com) on 12/15/11 wrote:
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>Mark Pillsbury (no_spam@gmail.com) on 12/14/11 wrote:
>---------------------------
>>I liked your thoughtful analysis but I respectfully disagree with your opinion that
>>"From a technical perspective, adopting ARM for SoCs makes little sense. It utterly
>>eliminates one of AMD's core competencies, namely their x86 expertise." I think
>>ARM is a better technical solution for tablets and netbooks/ultrabooks/notebooks
>>because power consumption is critical in these markets. A successful company has
>>to provide what the market needs even if it is not the sweet spot of their core
>>competency. Otherwise, it is like being the guy who drops his keys in a dark parking
>>lot and looks for them under a light instead of where he dropped them.
>
>There are folks here at RWT who know and can explain this stuff a lot better than
>me, including David, but the bottom line is that in real life, energy efficiency
>and power consumption has very little to do with the instruction set architecture.

I'd say that EVERYTHING ELSE BEING EQUAL implementing
a relatively clean RISC ISA has a 10-25% CPU core power
savings vs x86/x64 depending on uarch aggressiveness.

Two big HOWEVERS:

1) Everything else is *FAR* from equal. Differences in
process technology and design implementation quality/
methodology/power savings effort have at least a full
order of magnitude larger effect on core power than ISA
choice (at least among today's common commercially
used ISAs)

2) CPU core(s)'s portion of device power budget has
been consistently dropping. This means an increasing
portion of device power doesn't give a flying leap about
the choice of ISA.