Here's my set up. 2 X 3 GHZ Quad-Core Xeon 10GB 800 MHZ DDR2 FB-DIMM 4- 1 TB Western Digital Hard Drives 1- USB 1 TB external Hard Drive I replaced my original 500 GB hard drive that came with my system from Apple with the Western Digital 1 TB. I notice that the Western Digital Hard Drive is much noisier than what I had before. has anyone else experienced this? What should I get for my main OS drive? I want speed and quietness in the drive with reliability. Can my Memory be upgraded to something faster in my system? I notice that my computer seems to be a little slower and not sure if that has to do with all the hard drives I have on the computer. Thanks for the advice.