About a month ago I purchased a Nvidia GTX560 TI (Asus overclocked) and every game ran as smooth as planned.
However, since a few days I seem to be losing FPS for no apparent reason:
On light games, like Team Fortress 2, I used to have 120 FPS, which has now dropped to a (still playable) 50-60 FPS.
Heavier games like Bulletstorm used to run at a solid 60 FPS, but has now become completely unplayable with 5-9 FPS.
The weirdest part is that this doesn't happen immediately at the start-up of my PC, but rather after a couple hours of playing games. This could point at a overheating problem, but the card never gets hotter than 50°C
Once the FPS drop hits, it seems that my card becomes stuck in some sort of idle mode. Nvidia Inspector and PC-wizard both claim a temperature of 38 - 40°C, fan speed under 25% and a clock speed of only 66 MHz (while it's clocked at 900 MHz), even while playing games or using benchmark programs like FurMark.
The card keeps on doing this until I restart the PC. (Even a fast reboot seems to solve the problem for a couple of hours)
Anyone know whether this is some sort of protection, which hopefully can be delayed/disabled, or is there something more serious going on?