I noticed while playing Far Cry 3 that my performance was pretty terrible. I turned every setting to it's lowest and still experience terrible stuttering. Today, I tried Just Cause 2, which used to work great for me but I also get terrible stuttering with it. I'm not sure if it's because of my new CPU/Motherboard, or if my video card is dying or something.
Also, could it be the fact that I have three monitors connected (One via HDMI, one via active display port and one via DVI - A TV + 2 monitors)
ATI Radeon HD 6870 - Overclocked to 945 MHz GPU clock, 1160 MHz memory clock
Gigabyte Z77MX-D3H Motherboard
Intel i5-3570 CPU @ 3.40 GHz
24 GB of DDR3 Ram (SIW reports the speed as "667 MHz (667 x 2 = 1333)")
I did indeed. While looking at speedfan to see my GPU temps I noticed my CPU temps were very high. It turns out my CPU fan had fallen off (Fail), and when your CPU hits high temps it gets throttled a LOT. Probably not the same issue you're having, but check your CPU temps just in case