tokyotech

I currently have 4 x 256MB DDR2 400 MHz sticks on SDRAM. I want to toss out two of them and replace them with 512 MB ones. My computer supports both 400 and 533 MHz models that are unbuffered and non-ECC. On www.newegg.com, some of the 533 models are cheaper than the 400 models. Should I go ahead with the 533's? I am aware that the 2 x 533's will run at the same speed as the remaining 2 x 400's. Will the 533's slow down my computer more than the 400's because they are incompatible with the two remaining 400's? I've been hearing mixed responses on whether ALL sticks of RAM in the computer must be the same or just pairs of sticks must be the same...

This is my system:
http://www.crucial.com/store/listpar...on+4700+Series

For some reason, this page does not agree with my personal observations of the current RAM in my system, which are 4 of these: Samsung 256mb 1rx8 pc2-3200u-333-10-a1. PC3200 is not even listed on that site.