Why does my 980 ti keep downclocking?
I first overclocked it to 1472mhz, and it was stable in Valley. Occasionally it would clock down to ~1460. I then went into Witcher 3 and again, it starts at 1472, then downclocks to 1460, then 1450, all the way down to 1440's eventually. I lowered the core clock to get it at 1450 from the start, and it will again start downclocking, all the way down to 1430. In GPU-Z it states Pwr as PerfCap Reason. Does this mean my card just can't hit 1450+
Depending on the 980Ti you own (Brand and Model) some are restricted with regards to max voltage that can be fed to the GPU. However this generally only affects your overclock headroom/stability. If your card is down clocking then it is likely due to your card throttling in order to reduce its temperature.
What is you card getting to at 100% Load ?
Also let us know what brand and model as that will help :)