I have used Maxtor "SATA" drives that require
the O/S to do a "SET FEATURES :: UDMA_MODE" command
on them before they will operate reliably.
This despite the SATA spec stating clearly that
such a command should/will have no effect.

I suppose libata does this already, but just in case not..
Something simple to check up on.
-- 
Mark Lord
(hdparm keeper & the original "Linux IDE Guy")

William Knop wrote:

Ah, well all of them are Maxtor drives... One 6y250m0 and three 7y250m0 
drives. I'm using powermax on them right now. They all passed the quick 
test, and the full test results are forthcoming.