Blue Screens - Faster RAM Help?

Hey,
I have a giga-byte 8IEXP motherboard with a P4 1.8A processor. I currently have 512megs of Infineon 266 ddr ram. My problem is, I'm trying to overclock to 2.4 (133x18), but whenever I go to 133x2.0 for the ram, I always get blue screens in XP saying basically "Do a memory check...writing physical memory to disk..." etc. sometimes it happens right at boot, and other times I have gotten into xp and lasted about halfway through a 3dmark benchmark before it quits out,

The ram does work at 100x2.66 and 1.8ghz, and right now I'm running stable at 128x2.0 = 256mhz, with the processor at 2300mhz.

My question is - is this most likely ram related? Whould going to 333ddr help me go to 133x2? Does the reason it's not working have something to do with latency timings or something (which I don't think I can change)?

Any input would be appreciated.

also...would upping the ram voltage help at all? I don't really want to to do this, but if it helps I guess I will. My cpu voltage is at 1.575v.

In case you want to know, the only other components I have is a 60gb maxtor drive, a soundblaster live, and two burners. The power supply is a good quality 300W powersupply, and I don't think that would be the problem, but I may be wrong.

Thanks
Ian.