The RAM is OCZ gold series with 9-9-9 timings and runs at 1.65v
Have you had a read of the DX58SO Tech Product Specs yet? Page 15 refers to 1.5 Volt DDR3 being supported. If you have other (1.5 Volt) RAM which works fine with this board, you could always use that and try updating the BIOS to the latest version and swap the RAM back to see if that makes any difference, otherwise it'll be a case of using 'to spec' RAM.
I'm wondering if maybe I've just got to go in and set all the timings/settings manually for this RAM
Go do that even try it at 1066MHz.