[QUOTE=heliosh;470658]I'm curious how my rig compares to others in terms of power efficiency.
- Haswell i5-4690k stock clock, -100mV undervolted
- 2x8GB DDR3-1600 CL 9-9-9-24 at 1.35V
- 80+Gold PSU (BeQuiet E9 400W)

mprime 29.3:
FFT 4096k: 85W/145.15it/s = 586mJ/it
FFT 4480k: 83W/130.50it/s = 636mJ/it[/QUOTE]

My (and probably Mark's too) Kaby Lake i5 rig with single rank DDR-2400 (see thread on George's dream build) give or take a few % since numbers are from memory yields:
FFT 4096k: 420W/(7*170it/s) = 353mJ/it

[QUOTE=Prime95;470694]My (and probably Mark's too) Kaby Lake i5 rig with single rank DDR-2400 (see thread on George's dream build) give or take a few % since numbers are from memory yields:
FFT 4096k: [B]420W[/B]/(7*170it/s) = 353mJ/it[/QUOTE]
Is that 420W measured at the line, George?

[QUOTE=kladner;470697]Is that 420W measured at the line, George?[/QUOTE]

Seems about right: 60 watts per system. I'm just slightly higher than that, but I haven't undervolted as much as possible.

[QUOTE=Mark Rose;470700]Seems about right: 60 watts per system. I'm just slightly higher than that, but I haven't undervolted as much as possible.[/QUOTE]
The Kil-a-Watt says I am drawing 488 W, but that includes 7 HDDs, 2 GPUs (460 and 1060) doing TF, as well as the CPU.

As I mentioned previously, the reports I get on the CPU include two values:
CPU Power and CPU Package Power. The only way to make these numbers correlate with the 79-80 amps at 1.296 Vcore is to add them together. I think the Package Power must correspond to the "uncore" part of the processor, while CPU Power refers to the cores themselves.

Using this argument, my actual processor power is CPU 104 W + Uncore 114 W = 218 W. So 218/417 puts the system at 523 mJ/it. Add in the 6 W for the RAM and that goes to 537 mJ/it. This is versus 247mJ/it with just the core power considered.

[QUOTE=kladner;470702]
Using this argument, my actual processor power is CPU 104 W + Uncore 114 W = 218 W. [/QUOTE]
114W uncore is like a lot! Are you sure it doesn't include the CPU cores also? So 114-104W = 10W uncore?

114W+6W (RAM) / 0.85 (decent efficient power supply) = 141W at the wall?

[QUOTE=VictordeHolland;471280]114W uncore is like a lot! Are you sure it doesn't include the CPU cores also? So 114-104W = 10W uncore?

114W+6W (RAM) / 0.85 (decent efficient power supply) = 141W at the wall?[/QUOTE]
I wondered about that, too. However, Vcore=1.296 x 80 amps = [B]103.68 W [/B]shows that I should have questioned my original calculations and assumptions more carefully. You are correct. The actual PSU is Platinum, running somewhat below half capacity. I expect it is pretty efficient.
120/.9=133 W
104+10/.9=127 W

Can anyone recommend a multicore dev-board or compact compute package based on the ARM Cortex A72? I'd be interested to see how that compares in terms of this metric to an efficient Intel avx2 system.

Another question: Has anyone seen any numbers on how much power key individual arithmetic ops require on some laeding architectures? Especially FMA versus FADD is a comparison of interest.

[QUOTE=ewmayer;471509]Can anyone recommend a multicore dev-board or compact compute package based on the ARM Cortex A72?[/QUOTE]
The only dev board based on Cortex A72 that I could find is based on the Mediatek X20 (2×A72 +8×A53) but it costs $ 200...
[url]https://www.96boards.org/product/mediatek-x20/[/url]

[QUOTE=VictordeHolland;471515]The only dev board based on Cortex A72 that I could find is based on the Mediatek X20 (2×A72 +8×A53) but it costs $ 200...
[url]https://www.96boards.org/product/mediatek-x20/[/url][/QUOTE]

Yes, I saw that one too, obviously pricier than my humble A53-based odroid - though not on a total-FLOPS basis - but lowest cost option I've seen so far.

Perhaps Tom Womack, who did the A57 timings over in the Mlucas-for-ARM thread, has or can get access to an A72 by way of his working at ARM. He specifically mentioned possible access to some Cavium Thunder-X machines, but not clear to me which precise Cortex processor those SoC server processors are based on, A72, or an earlier one. [It's not made clear in their PR, e.g. [url=http://www.cavium.com/ThunderX2_ARM_Processors.html]here[/url].]

Just PMed him a followup about that. The Cavium servers are specifically designed as a low-power competitor to Intel's Xeon server line, i.e. as a business-class embodiment of the theme of this thread.

It looks like that Helio X20 based board doesn't support Linux. That's quite sad but many ARM boards only have Android support and very bad Linux support (if any).

Firefly RK3399 board supports Linux: [URL]https://www.amazon.com/Firefly-RK3399-Computer-Reference-Development/dp/B06XSCT11S[/URL]

No first hand experience though :smile:

BTW ThunderX CPU is proprietary.

A73 based boards are also worth considering. This gets 4 of the big cores rather than 2.
[url]https://www.96boards.org/product/hikey960/[/url]