You like I.......Trusted the marketing hype that the Marvell on board chip would support sata 3 out of the box..........unfortunately if it carries the Marvell logo the best you will get is sata 2 performance........even the ICH10R will outperform the Marvell ports.
The only way you'll get rid of the bottle-neck, reach Sata3 speeds and intermittent connection is to install a quality PCI based raid card... one suggestion is the RocketRaid 640-4 port card that will support boot to OS.....it'll set you back about a hundred fun tickets and save you many hours of fruitless research and testing...... if you don't believe me, just search through this site alone and you'll get the picture.
Aussie Allan