Since you say you're starting to get lag and slowdowns in more current games, start with a video card upgrade. It will give you more overhead for the more demanding games, and then you can always save up for a new mobo/CPU/memory combo down the road.
One last question: I've been offered a rather good deal via Craigslist on an AMD motherboard, and was wondering if it was decent. It is a ECS IC780M-A (specifications). I would just hold on to it for awhile until I could afford a processor, but I can't figure out whether it would support an X4. Besides that, is this a decent board for a future upgrade?
$25. I've never considered motherboard chip set before. Does it matter that much? What should I look for? With all the different brands its hard to compare different north bridges. I'm not going to be OCing. Also, I'll probably be using an Athlon 64, which has a built-in memory controller.
Since you say you're starting to get lag and slowdowns in more current games, start with a video card upgrade. It will give you more overhead for the more demanding games, and then you can always save up for a new mobo/CPU/memory combo down the road.