Just for info, my motherboard is the Asus P5B-E, I upgraded to beta 4 without a problem but with "Force NCQ Disabled" set to ON my Parity sync speeds dropped from about 96Mb/s to about 29Mb/s and my transfer rates from about 25Mb/s to under 1Mb/s. It's not a problem as I just set it to OFF but I thought somebody might be interested.
Santan.