That would have been a great question to ask tomshardware forums in early 2004, I doubt anyone here remembers exact numbers.
Your best bet is to start off with a small 5% increase in GPU Overclock, stress test the video card to make sure there are no stability issues then do another 5% until you see artifacts or instability issues.
Next do the same with your Graphics Card's RAM.
By the way I brought the NVidia FX 5200 in January 2004.