Hi all,
I have a HD 7970 that appears to keep clocking down to 2d mode (500Mhz) instead of staying in 3d mode (1000Mhz)
I have had to modify the cooling because it did not fit corectly and the GPU was overheating. Would easily reach 97 deg C with stock cooler. I believe the die was manufactured incorrectly because the metal shield around the die was taller then the die its self, So i milled off the excess corners of the copper surface off an Artic Accelero Xtreem Plus II.
Now she runs much much cooler, usually around 70 deg C.
I say it was a Saphire 7970 because in an attempt to fix this speed cycling issue, i have flashed it with the 7970 Ghz Edition firmware. And it all works perfectly, but i am still having this issue.
This is happening with DiabloMiner and poclbm.
I am now using cgminer with these settings...
"intensity" : "9",
"vectors" : "1",
"worksize" : "256",
"kernel" : "poclbm",
"lookup-gap" : "0",
"thread-concurrency" : "0",
"shaders" : "0",
"gpu-engine" : "1000",
"gpu-fan" : "0-100",
"gpu-memclock" : "0",
"gpu-memdiff" : "0",
"gpu-powertune" : "0",
"gpu-vddc" : "0.000",
"temp-cutoff" : "97",
"temp-overheat" : "95",
"temp-target" : "85",
"api-listen" : true,
"api-port" : "4028",
"expiry" : "120",
"failover-only" : true,
"gpu-dyninterval" : "7",
"gpu-platform" : "1",
"gpu-threads" : "5",
"hotplug" : "16",
"log" : "5",
"no-pool-disable" : true,
"queue" : "2",
"scan-time" : "45",
"temp-hysteresis" : "3",
"shares" : "0",
"kernel-path" : "/usr/local/bin"
And here is a screen shot over GPU-Z while running cgminer for a couple of minutes...
http://vitl.co.nz/7970-Mining.jpgYou can see the GPU cycling down quite often.
I have just tested the GPU while playing crysis 3, and i did cycle down, so i though i would try lowering the voltage on my 12V rail, it was set to 12.8v, and is now set to 11.5v.
Crysis 3 ran at 1000Mhz for the full 10 minutes i was playing it. But bitcoin mining is still giving me issues.
Does anyone know what on earth is going on here !?!?
Update 1:
The behavour appears to be a function of the temperature, it will cycle down when the card goes over 55 deg C.
I am starting to wonder if i need a heat sink on what looked like the oscillator on the board.
Update 2:
I have just put heat sinks on what i believe are transistors for the power circuit....
http://www.vitl.co.nz/front_full.jpgAnd it has improved a little but still not good. It still starts to cycle down to 500mhz @ 55 deg C but not as often.
Putting a fan heater on fan mode against the card appears to almost fix the issue, but this is far from ideal.
Update 3:
Something interesting happening...
As soon as the core clock goes over 1000Mhz, the core voltage switches from 1.072v to 1.119v.
And only when that happens, the card will cycle down to 500Mhz periodontally.
Update 4:
Getting VERY good results using Saphire Trixx by lowering the voltage.
Download:
http://www35.zippyshare.com/v/4022846/file.htmlUpdate 5:
Purchasing water cooling system.
Lowering the voltage did help a lot, bit it still all depend on the temperature.