Speed Discrepancy between two 1TB Velociraptors?

[D749]

I have two 1 TB Velociraptors installed in my system. The drives are not install in RAID and each is connected via a SATA cable to my motherboard. I've test each using different ports and the same port just to rule that issue out. Both driver were purchased new. Both drives pass the WD Data Lifeguard Diagnostic tests. Neither drive is being used as system drive (no OS or swap files are stored on these drives).

Is such a speed variance within a model line typical? Does the amount of used space on a drive have any impact on how the drive benchmarks? For what it's worth the "newest" of the two drives (e.g., I bought one drive ~1 after the other) is the faster drive.

Thanks.

[Highendtoys]

It's because one has more data on it than the other. The data gets stacked on the fast part of the drive. As you fill it the data gets put on slower areas of the platter.

You might be able to find a video of the clear cover Raptor. The fast part of the platters is the outside, where the blocks move faster over the heads. The closer you get to the center, the slower the drive.