I used the auto timings, but set them manually, just because.

so, 4-4-4-12-3-42-6-3-8-3-4-5-4-6-4-6.

Static read ENABLED.
clock twister and transaction booster on auto.

My E660 will do 266 strap up to 520mhz FSB on other boards...strap issues are still prevalent on this board, so it's probably just some setting affecting your build.