WD15EARS-32MVWB0 - much slower than 00MVWB0?

Hi,
I bought Western Digital Green 1.5TB drive WD15EARS-32MVWB0 (made in November 2010) and I found it to be much slower in comparison to 00MVWB0 version. I saw benchmarks of WD15EARS-00MVWB0 (having 667 GB platters) showing 122-65 MB/s read speed with average 98 MB/s. My 32MVWB0 drive has only 97-36 MB/s with average 72 MB/s, which is even slower than old 500 GB platters version and 36 MB/s at end of the drive is very poor performance.

What can be the size of platters in 32MVWB0 and why is it so slow? Drive is alligned correctly (partitioned & formated in Windows 7 x64). One week ago I had Samsung F2 in PC and it was much faster (88 MB/s average), but also louder…

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Weight of my 32MVWB0 drive is 628g, which should correspond to 3 platters drive. I don’t see any reason why it is so much slower than 00MVWB0 and still a bit slower than one year old 500 GB platter models. I would think that it shold be also 667 GB platters disk, but speed difference 72 vs 98 MB/s is too big.

SMART shows no erros, short test in WD Data LifeGuard Diagnostics passed without errors. Benchmark results are the same from Win7 x64 and WinXP…

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