GPU Utilization Rapid Fluctuation - GUIMiner

[cwickstylz]

I've been mining for quite some time now & just recently added an additional 7970 to my main rig.  I've currently got an MSI R7970 Lightning & a Sapphire 7970 Ghz Edition Vapor-X that I just added.  I do not have them crossfired, as I hear it's better to just let them mine independently, right?

The question I have is this.

Generally my 7970 Lightning sits at 99% utilization 24/7 with no issue.  The 7970 Ghz Edition does some quirky things though.  I've been keeping an eye on the utilization of it & whenever it peaks & actually hits 100%(which my Lightning never actually does), it drops down for a matter of seconds to about 60% utilization.  It then goes right back up to 99%, but then a few seconds later hits 100% & process starts all over. 

It's not a huge issue, but I'd certainly prefer to just have to churn away at a steady 99% like the other card, as I'd assume a steady utilization has to be better for the card than bouncing back & forth every few seconds, right?

Any ideas?

Thanks!

[hedon]

Try to set in AMD Overdrive "Power control settings" +20%,
or directly in cgminer --gpu-powertune 20

[brinebold]

I'd take a look at http://www.techpowerup.com/downloads/2221/TechPowerUp_GPU-Z_v0.6.9.html and run GPU-Z to check whether your card is overheating and downclocking. If so, I would recommend pulling the clock speed down to a level where it doesn't do this. This constant downclocking is putting your GPU through massive amounts of thermal stress (orders of magnitude more than running at 99-100% constantly even if it is on the upper edges of the GPU specifications).

Also, clean out your GPU fan if you haven't. Dust might be causing overheating even at stock clock speeds.