Generic Multiple GPU discusssion

My box with one 5700 plus one 6800 (neither of these is an XT) should be quite a bit over 3 million on the high-pay GRP work recently being issued.

I've had trouble that appears to take the form of the AMD driver suddenly deciding to downclock the 6800 quite severely.  While nominal is up near 2200, and I was running it purposely near 1950 as a single (for power conservation and temperature reduction with little computation output lost) and was running it about 1400 in the double configuration (for yet more power reduction and temperature margin), it would suddenly drop temperature by about 10C and stay there for hours.  When I'd check the clock speed it would be remarkably low--something near 500.

Just this morning I noticed there was a new WHQL driver update from AMD, version 21.4.1 of April 20.  I'm interested to see whether any of my driver/clock rate/fan control oddities seem to have improved in this release.  Initial indications seem possibly promising.

With one day of running this new driver release I can report that my undesired major stable downclock went away entirely.  So far the system seems stable.   With the current "high-pay" GRP tasks the apparent system production is right about 3,400,000/day.  I think it very likely the driver is the difference.  Of that 3.4M, the 5700, an XFX in mining mode with -40% power limitation imposed, is contributing somewhat over 1.4M, while the 6800, held back by a 1400 MHZ clock limit, is doing a bit under 2M.

My previous plan was to run the two-card high-capability, high-power configuration just for the current cold snap, then pull out the 5700 for the summer.  My new plan is to have a try at using the capability the undesired major downclock showed me by intentionally configuring a two-card low-power configuration for summer.  At the most extreme I could probably run 1X (instead of the current 3X), with the 6800 set to about 500 MHz GPU clock and the 5700 set to -50% power limitation.  Just to see the full range of possibility, I currently intend to do a trial run at those settings this weekend, which is forecast to be hot here.  Then perhaps I can fill in some intermediate possibilities and give myself a configuration menu for seasonal adjustment.  Not opening up the case to add and subtract a card seems good.

I got a pause in task fetching overnight, as the daily quota for this configuration of 1024 was not quite enough.  So I've raised my cc_config overstatement of the real number CPUs from 16 to 24.