Moved it onto my Intel (SATA2) controller and it's actually quicker than the Marvell (SATA3) one. Poor chipset, the Marvell one, lots seem to be having problems with S3 devices.
Soo, bit the bullet and decided on a Sandybridge upgrade. Should be more than the storage running quicker
Yes the Marvell controller is rubbish for high performance SSDs, I purchased a board with SATA3 Marvell ports on them and ended up going back to the Intel controller which gave better performance even though it was SATA2.