I recently discovered a new tool that has helped me to ensure that my Overclock is stable, and I wanted to share the info. I have tried many tools to ensure a stable GPU overclock, but the following are the best I've come across, including the 3rd new one! Read on :)

Previously, my 2 tools were the following (which I still recommend!):
- Run the Heaven benchmark, at maximum resolution and Antialiasing and tessellation, full-screen, overnight. If it crashes or leaves leaves a TDR .dmp in C:\Windows\LiveKernelReports\WATCHDOG, then the overclock is unstable
- Run GPUGrid tasks, and inspect the results on the web; even look at the successful ones; if any task ever says "The simulation has become unstable", then the overclock is unstable

My new tool is to continuously run a complex PrimeGrid Genefer OpenCL calculation.

Specifically:
- Download the latest PrimeGrid Genefer OpenCL app
(current version is: http://www.primegrid.com/download/primegrid_genefer_3_3_1_3.13_windows_intelx86__OCLcudaGFNWR.exe)
- Open a Command Prompt window
- Run with the following arguments, including the double quotes:
primegrid_genefer_3_3_1_3.13_windows_intelx86__OCLcudaGFNWR.exe -q "43322502^131072+1" -d 0
- If the application completes successfully with a .log file that has "is composite. (RES=" in it, then you are short-term-stable.
- If you want to run on a different GPU, change the -d parameter
- Another good test is to swap out that number in double-quotes, with this number: "43370168^131072+1"

So ... to REALLY use this method to ensure stability, I recommend putting it into a loop, and running it overnight.

You can create a .bat file, that has this in it:

FOR /L %%G IN (1,1,200) DO (
primegrid_genefer_3_3_1_3.13_windows_intelx86__OCLcudaGFNWR.exe -q "43322502^131072+1" -d 0 > 43322502_d0_%%G.txt
primegrid_genefer_3_3_1_3.13_windows_intelx86__OCLcudaGFNWR.exe -q "43370168^131072+1" -d 0 > 43370168_d0_%%G.txt )

I have used this method to successfully determine that my brand new EVGA GTX 980 Ti FTW GPU .... was actually overclocked TOO MUCH by the factory! I have to apply "-20 MHz" to the Core Clock in MSI Afterburner, in order for it to run that .bat file overnight without error.
---shakes head at EVGA---

Yeah, I've previously had to downclock an EVGA GTX 660 Ti, due to factory overclocks that were too high. Sad, really. I didn't realize overclock stability was a concern, until it had crashed and ruined 2 of my long iRacing races. I learned a lot back then.

:) I have 2 GTX 980 Ti GPUs in my new system here - the other one is a reference-clocked Dell. I've used these 3 overclocking stability tools/methods, to find its maximum stable overclock, and am extremely happy that I'm able to apply a "+170 Mhz" to the Core Clock and remain stable.

In fact .. my Dell GPU, at boost, runs at a faster clock than my pricey EVGA FTW! I'm even using the Dell to drive my single display for my games, because of that. I'm not sure if I got lucky, or if it's normal to be able to outclock a FTW, but I am still surprised.

For both of these Maxwell GTX 980 Ti GPUs, the PrimeGrid Genefer test was the most-stressful (and most useful) of the 3 tests. So much so, that I felt obligated to write the first post hehe. I'm looking forward to more GPUGrid tasks to test my new GPU overclocks with!