Why spend anymore money, you already know that the ICH10 controller is faster, why not just use that instead? I know you want to get the SATA III speed, but its clear that its not implemented correctly by marvel. You will never get SATA III speed on a marvel controller, and that is all that available for the LGA1366 socket.
I just did a little experiment and ran AS SSD benchmark with my SSD on the 6gig marvell and then tested it again on the Intel 3gig connection. Results were interesting... All benchmark numbers were slightly lower on the SataII connection compared to the marvell SataIII connection. BUT the 4K-64THRD read result was 7k IOPS / 26MBps
and 42k IOPS / 165MBps
on the Marvell and Intel connections respectively. My overall benchmark score on the Intel chip was 466 versus the marvell at only 279.
This was surprising, but somehow expected. I guess it is probably better to stick with the SataII Intel controller. Boot times are identical it seems. Heck, if i disable the marvell, boot time will obviously be decreased due to the controller not having to POST.