Problems with game performance

Frames per second lag, in game, can be found by hitting tab. Check the lower corner of the box. Watch the amount of frames you get per second, check them periodically. I recommend checking them at all times during the game. Try to find a trend. If the fps lag is spiking for what seems to be no reason then see if there are programs running in the background that shouldn't be. When I had this problem, I could not figure out where my fps lag was coming from. Turns out that it had nothing to do with the game. My friend had used my computer to print coupons out from an reputable site and ended up downloading adware that affected my performance. Once I removed the adware, the problem seemed to go away. Try different things. It could just be that your computer is running too many processes at the same. It could also be that you need to update your graphics card.

Also I recommend doing some port forwarding if possible. Might not help with the lag completely, but should help stabilize it. As for the fps lag, (if that is what you're talking about.) Make sure that the rooms you're playing don't have multiple things going on. Such as but not limited to, tons of people shooting at once, someone spamming chat, or multiple smokes/flashes/HE nades going off. By the way, old video cards can handle cf just fine, if an ATI ATX 300 can run cf then even a nvidia 9800 gt can run without even trying. So your video card isn't the problem. (unless you need to update your drivers.)