Mine 750ti's are doing great, except one is only doing 500ish kh/s not sure why.
That happens to one of mine a lot. Gpu 2 starts throwing errors like crazy in ccminer. I close and restart ccminer and it stops with the errors but only hashes at 500. Normally a restart fixes it.
I have no idea what causes it. My rig can run fine for weeks and it just happens out of nowhere. Always gpu 2