I'd probably work my way up from a FSB of ~384MHz (384 x 7 = 2.69GHz), at a Vcore of ~1.30V and VTT of ~1.40V = an effective DRAM clock of 768MHz (DDR3-1536) at x4.00. The problem is that your BIOS doesn't offer a VTT option (only options are Vcore, DRAM voltage, and vNB), which the Q8200 needs quite a bit of in order to reach the higher bus frequencies. And vNB shouldn't need to increased past the default for that low a FSB on the P45 chipset.