各位有看 anandtech 的測試嗎?
http://www.anandtech.com/storage/sh...aspx?i=3269&p=2

WD 有稍微解釋 3200aaks-b3a 的緩慢搜尋時間:

Quote:
....After a lengthy conversation with Western Digital, we now understand why the drive performed so poorly in this test. This also explains the good but not great application results in general. Granted, the drive still performs well, but the initial specifications lead us to believe that performance should have been greatly improved over previous generation drives. Western Digital explained the single platter 320GB drive is aimed at the entry-level market where thermals and acoustics are critical for mass acceptance of the drive by the OEM and retail customers.

WD sacrificed a small amount of performance on the 320GB drive to meet these goals.....

簡單結論是 WD 把320gb 定位成入門級產品 (希望不是減料)
為了減低噪音和熱能而犧牲了 3200aaks 的部分效能
測試結果3200aaks 的確比 6400aaks 安靜一點點