Quote from: pbfarmer on March 28, 2019, 04:53:31 AM

Quote from: kerney666 on March 27, 2019, 09:58:45 PM

Quote from: pbfarmer on March 27, 2019, 09:44:31 PM

Haven't really done much in the past w/ CN light variants, as I got the impression they were a bit more power hungry... Is that the case w/ this (e.g. compared to cnv4)? Just so I can get a sense of where to start my voltage settings.

Not trivial to measure, there are a few different trade-offs in play, but I'd actually say they're about on par. CN-turtle uses the CNv8 main loop which (in our case) draws less power than the CN/r main loop, but CN-turtle does for sure put more load in general on the gpu than the 2MB pad variants.

Ok, only Vega 64 for now, and only from a single GPU (though voltage needs should really be the only variable moving forward w/ addl GPUs). Will try to post VII and 590 numbers later:

Env: ubuntu 18.04 + amdgpu-pro 18.50.
Best cn_config - based on initial test: L28+28 (see table below)

Test desc	\|GPU (actual cclock, mclock, mv)	\|Miner h/r (kh/s)	\|Power ATW
\|CNR settings	\|1390 MHz, 1107 MHz, 825 mv	\|19.60	\|?
\|mclock+	\|1390 MHz, 1145 MHz, 900 mv (not tuned)	\|20.18	\|?
\|mclock+, cclock--	\|1210 MHz, 1145 MHz, 862 mv	\|20.14	\|~170w
\|Final settings	\|1210 MHz, 1107 MHz, 806 mv	\|19.54	\|~150w

Notes:

Definitely lower power requirements vs cnv4/cnr if tuned properly
Algo performance is heavily dependent on mem bandwidth, not so much on core clock speed.
- Increasing mclock from 1107 to 1145 gave ~+3% h/r, but at a heavy cost (+13% power) due to SOC scaling to 1200.
- Dropping core clock from ~1400MHz to ~1200MHz only reduced h/r by 0.25% (19.60 to 19.54 kh/s) - all the way down to ~1100MHz still gave 19.45 kh/s, but 850Mhz resulted in ~12 kh/s, so there is a cliff somewhere, or maybe I needed to re-adjust cn_config
- I didn't do any more tests reducing cclock further, as I was already down to the voltage floor at 806mv/1200MHz. However, if we can go significantly lower (like ethash,) we may be able to save enough power in cclock reduction to make an mclock boost worth it???
- Finally another algo that would seem to make the 56->64 flash worth it.
cn_config 'L' variants not only had better h/rs, but seemed to also put less pressure on GPU, therefore requiring slightly less power
Windows 10 pro w/ 18.11.x drivers produced exact same results at my efficiency settings in linux, so didn't bother testing further. In general, I find w/ most algos that as long as the effective (under load) clocks match, h/rs and power use will match as well. The only real diff between linux and windows is the cclock setting required (much higher) to get to your desired effective cclock.

cn_config	hashrate	___	___	cn_config	hashrate
L28+28	19.60			28+28	19.32
L28+30	19.57			22+24	19.32
L26+28	19.57			24-24	19.32
L26+26	19.56			20+20	19.30
L24+24	19.52			23+25	19.08
L20+20	19.48			25+25	19.06
24+24	19.44			L30+30	19.06
L28-28	19.39			22+22	19.01
24+26	19.36			23+23	18.95
26+26	19.34			L27+29	18.89
26+28	19.33

Great analysis, pbfarmer!

I'm gonna give my 56's more of a test run later. I run them at XMR clocks currently - which means I'm feeding them unnecessary core clocks and voltages. But even then the cards aren't sucking much power. I'll report later... when I get some time to test Tongue