Like BIB stated...about 150 or so will be about the max on Kingston PC2100 and that is using 2.9v's...as cheap as PC2700 is getting...best to get some descent PC2700...even the Kingston PC2700 value ram can run at 5-2-2 cas 2 up to between 175 - 180 or so...but it will max out between 190 and 200 and if you are lucky you might be able to get it past 205, but not by much...I was able to get my old PC2700 value ram at 208FSB but that was running some really relaxed timings...and some high voltage...plus I added heatspreaders to them...and no, if they are installed correctly Kingston will still warranty them with aftermarket heatspreaders...emailed them before I added mine...