Overclocking. Second GPU sits at 50% usage.

[TheNaitsyrk]

Hey,

 

Today I decided to see what my GPU's in SLI are capable of. I overclocked as much as possible until crash, then I raised Power Limit in EVGA Precision X to 103%.

 

Then I overclockd by 10 core clock. Worked fine.

 

Then I overclocked by another 10. (Total 1100 overclock).

 

I run Heaven 4.0 and I see sudden FPS drop. I then checked GPU usage and 2nd GPU usage was 50%.

 

I thought it's a power limit issue so I raised power limit to 106% (maxed it out).

 

I ran the benchmark again, and the 2nd GPU was still sitting at 50% usage.

 

I then clicked default to make everything normal again whilst running the benchmark and the 2nd GPU was still at 50% usage at stock clock.

 

Any idea what happened and how to fix it?

[Toddwjp]

what psu and cards do you have,

 

also welcome to the world sli and overclocking bugs that will probably never be fixed

[TheNaitsyrk]

780 TI in SLI.

1000W Corsair GOLD PSU.

 

1090 clock (boost 1220 worked fine)

1100 clock = FPS drop and 2nd GPU usage 50%.

Reverted back to old settings, 2nd GPU was still sitting at 50%.

[Hieb]

what CPU do you have

[TheNaitsyrk]

4790K.

[Hieb]

hmmm weird. temps are ok, i imagine?

[TheNaitsyrk]

Temps are as should be. Accordingly to Precision X. Power Limit says 95 degrees if I make it 106% but they sit at 83 and 82 degrees all the time.

[ProKoN]

does it run fine at stock gpu clocks?

 

what are your results if you run Valley?

[TheNaitsyrk]

At stock it runs fine. With +149 OC works fine. Then When I up it to +159 core clock, 2nd GPU just say "nah" and works at 50% instead of 95-100%.

When I test in Heaven 4.0 I get more or less even results between +139 and +149, that's why I was uping everything to see how far can I get.

[TheNaitsyrk]

Now I used different software to overclock (MSI Afterburner instead of Precision X). Managed to get +180 and it worked fine, however the core clock on both cards stayed 1215 and I thought that each +10 increase would show that I got that increase? I'm a little bit confused. The Heaven 4.0 score was about 35 points lower everytime I upped core clock by 10 which is strange.