I'm using 2x 512mb Centon PC2100 DDR that I got from newegg back in Dec of '01 it's rated at Cas 2 and works fine w/ fast timings in my K7S5A, at the time it was like around 50 ish dollars cheaper than any other cas2 memory newegg carried, so far I haven't really been disapointed w/ it and it works as advertised, just don't expect to use it to go over its rated speed