9800 Pro with slow fps!?!

I've posted before about upgrading my motherboard to AGP 3.0 and found out its impossible. OK well i'm stuck with running 4x speed, no big deal. However when i'm running Counter Strike: Source i continually get below 70 fps. Now I've checked chipset drivers, vid card drivers, agp fastwrite... you name it. I've got a Asus P4PE motherboard with p4 2.4ghz and 1gb pc2700. Now i've got a 380w psu and 9800 pro requires a 350w. Could that be the problem or am i missing something else? All in all the 9800 pro should NOT be giving me below 70fps (sometimes down to 20) when people with Radeon 9200's and comperable Nvidia cards are getting around 100 fps with less ram and slower processors. I've also checked available ram when playing and i've got 750 to 800 mb worth of ram free on my system.. What could it be?! Its driving me crazy. Thanks in advance