The newest 7200rpm drives have pretty much caught up with the performance of the WD Raptor hard drives, but now WD is upping the ante with the new Velociraptor drive.
The most interesting reviews can be found at
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Interesting point - SPECapc scores improve by about 7.5% when comparing the Velociraptor and top performing WD RE drive in an otherwise identical system.
VERY interesting point - A single 3.0 GHz Core2 Quad system with unbuffered DDR2 memory outperforms a dual 3.2GHz Core2 Quad system with fully buffered DIMMs by 9%! (Read both parts 1 & 2 of the review and compare benchmark scores.)