I'll probably jinx myself, but I've been using the cheaper memory in my PB for a few months now with no noticed ill-effects. I purchased some Centon PC3200 DDR400 memory from CompUSA. But first I took a close look at it vs. the "Apple Certified" PC2700 DDR333 version. Same brand. The chips themselves looked exactly the same, even the part numbers were almost identical with a slight difference which I assumed was probably due to the difference in speeds. Layout exactly the same. Board exactly the same. Manufacturing looked exactly the same. So I figured I'd take a shot since the non-Mac version was going to be $160 cheaper (after M.I.R. of course). So far it seems to have paid off. matt.