Actually, Crucial Ballistix is spec'd to run with exactly 2.80v, @200 Mhz. It's known to fail (be ruined, not fail Memtest) with 2.9v, but can usually attain 250 Mhz with 2.8v. Just start raising the timings, as you run it faster. 2.5-2-2-5 @ 225-230 Mhz, 2.5-3-3-6 @<240, etc.