For the past little while, I've been using RivaTuner to overclock my ASUS V3800M card. I've squeezed a small amount of performance out of it- here's a dumb little chart showcasing a small preview:

Stock, 100/150:
1024*768*16, 16-Bit Z-buffer, Triple Frame Buffer: 3490 3DMarks

OC, 100/185:
1024*768*16, 16-Bit Z-buffer, Triple Frame Buffer: 3881 3DMarks

The card runs at a stock frequency of 100MHz for the core clock, and 150MHz for the memory clock. The core clock cannot be changed, but so far I have managed to get the memory clock to a maximum of 189MHz (the maximum "safe" frequency that RivaTuner gives). I pushed the memory clock up to 200MHz for a brief moment, but I started seeing graphical corruption on Windows 98, so I turned it back down to 185 and I've had it up at 189.

Is there a way to get a higher core clock? It just resets to 100 every time I try to push it any higher than stock speeds.

[EDIT]

Even when using the coolbits registry option to allow overclocking through the nVidia driver control panel, the core clock still does not go over 100MHz, but the memory runs fine @ 185MHz.