Newb Memory Question

I have 2 dual Wintec DDR-SDRAM PC2700 - 512mb chips running on my ASUS P4C800E-DELUXE with a P4 2.4B Processor.My question is...I have my cpu overclocked at 2.88 set on 20% auto increase, what would be the best setting for my memory since im new to all the overclocking excitement? Right now it says its running at 266mhz, when i change it to 333mhz (which im pretty sure this memory is) i get a blue screen and it reboots.Please help this poor newb with straight to the point answers, im slooooow.

Thanks!