I don't know which cards are good for overclocking.
PC2100 is, as you know, not designed to run at 150 MHz but sometimes it will, at first disable ECC check and maybe it will accept higher speeds. If you test your system with only the videocard, CPU and mem. in it and it's not stable you can try if getting some PC2400 (or higher) memory fixes that.
My case has so many fans that it hovers above the ground