One more for cas3 pc133. I had some pc100 at 2,2,2 and it worked very good. It gave me excellent benches also (better than the p3 1 gig in sandra). Now I am using the virtual channel pc133 (3,3,2 by spd) set at 2,2,2 and it is even better. The difference is not huge, but is enough to spend a few extra dollars for the pc133 if your in the buying market. If you already have some pc100 working fine then you should be satisfied. If it's really good pc100 then try setting it at 133? You may not get 2,2,2 out of it but 3,2,2 might fly. Mine would not even at 3,3,3.