First verify: What driver are you using? are your partitions aligned?.
Down load and run AS SSD (no need to run the bennchies), just open as ssd and look at the upper left. Driver should be either msahci or an amd driver. Partition algnment should indicate "OK"
I think you find that most reviews are done on a intel platform and AMD driver is not quite as good as intels iaSTor driver.
Will post a scrren shot of my M4 in a laptop.
Added: Firmware is a snap, just vist Curcial Wbsite for down load an instructions.
My 128 Gig M4 in laptop:
http://i55.tinypic.com/nbq5xj.jpg