Please take a look at the following pics. These drives are all Western Digital 250gb SATA300 drives. Model WD2500KSRTL. 16mb 7200rpm. Please note the 2 differences: 1. Color of the enclosure cover different. 2. Spindle motor differences The "silver cover" drives have 2 different motors being used. The "black cover drive" uses the copper colored motor only. Question: Should a company manufacture a product with the same model number in which there are 3 different variations? What other internal or electronic differences may be unscene? How do they co-opperate in a RAID configuration? Personally I like all the wheels on my car to match. I like the lugnuts on the wheels to match. I like all 4 doors to be the same color. I like all the screws that hold in my cdrom to match. I like my videocards to match. I like ddr-2 in matched pairs. I expect my quarter pounder to taste the same as it did at the McDonalds 1000miles from here and what do you know, it does. ect ect ect. Why should I have to test each of these drives to see which is better? Now I have to wonder if this is a screwup. Could one (or more) of these drives be 8mb cache? SATA 150? I have to doubt this whole company now. Another note: The "black cover" drive is louder and hotter then the "silver cover" drives. The copper colored spindle motor is hotter on a "silver drive" then it is on a "silver drive" with the chrome motor cap but all "silver cover" drives are equal in read/write noise but the "copper cap" motor makes a louder whine. Also the "black cover" drive vibrates in my hand. That will trash the spindle bearing sooner. I KNEW I shouldn't have bought WD. I had given up on them years ago and switched to Seagate but the cost was right and the noise level is less then my Seagates.