Re: Steep FPS loss after 5 Minutes
You say the temp on the GPU is ok - is the CPU temp ok as well? If it's fine for the first 5 minutes it seems unlikely that it's a lack of horsepower causing the issue.
My first thoughts are (temps aside) that it could be a driver issue, or some other software interfering with the program. I've also seen similar behaviour on a GPU that it turned out was slowly dying - so don't rule it out just because it's not getting hot, it could still be the GPU at fault.
Save the whales, feed the hungry, free the mallocs.