From my review:
400MHz (DDR2-800), 1.9v, 4-4-4-12-13
450MHz (DDR2-900), 2.1v, 4-4-3-12-13
500MHz (DDR2-1000), 2.1v, 4-4-4-12-13
533MHz (DDR2-1066), 2.3v, 4-4-4-12-13
575MHz (DDR2-1150), 2.4v, 5-5-5-18-13
600MHz (DDR2-1200), 2.4v, 5-5-5-18-13For 1:1, I'd try for 450MHz.