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Old 2012-08-24, 15:05   #5
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fivemack's Avatar
Feb 2006
Cambridge, England

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Originally Posted by ldesnogu View Post
The problem with that setup is that the ARM cluster is made of 6 full boards. That setup is said to idle at 15-16W and observed peak power is 31W.
There are a couple of startups who've tried to attack the problem of the high power consumption of idling x86 systems - Seamicro's SM10000-XE Sandy Bridge machine piles up low-voltage Xeons, avoids duplicating motherboard peripherals, and 'reduces the power consumed by the CPU by consolidating and powering down unused functions', though its web page only gives an 'average power consumption' figure and that's 3.5kW for 64 quad-cores.

I've not got a good handle on the power consumption of DRAM, though I've heard disconcertingly high figures on the order of one watt per gigabyte at idle - that gives a slightly unfair advantage to the unfortunately memory-constrained ARM systems.

Anyway I think that for many FP intensive tasks IVB would be more power efficient. Perhaps with ARMv8 and proper FP SIMD support will things change.
Yes, ARMv8 has double-precision SIMD, but it's roughly SSE2-level: operations on only 128 bits at a time.
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