Hi Guys, I replaced my main drive, the 320GB with a 750GB Samsung F1. It seems to work fine. However it seems to have set up some sort of sympathetic vibration in the Mac Pro, which sounds like Hummm Hummm Hummm. Where as all the other things that cause noise in the case are a consistant and steady tone, this one is not. It's driving me nuts. Is this normal to be making this noise? I've tried it in different bays and it makes no difference. Any idea? UPDATE I've taken all the drives out except the F1, as I installed another DVD drive and three HD's and the noise has gone, so I'm now going to load each drive and review.