I have a X1300 Pro in my office computer and it's nothing special. It wont run games like Rainbow Six: Vegas without hesitation and I know it's not the processor that's the bottleneck. The only thing I can get it to run is Madden and it still freezes after the play is over. Unfortunately if your MoBo doesn't support PCI-E or AGP you're probably going to need to start over. Without that MoBo as a solid backbone you really don't have much to build on. If cost is an issue and you can't swing a full build at once may I suggest buying an off the shelf computer with good CPU and a PCI-Express slot and upgrading the graphics card, PSU, and RAM as you get the money. Rome wasn't built in a day. Good luck!