I am upgrading my system today. My mobo is: Gigabyte GA-P35-DS4 My old RAM, which works, is DDR2 - 800 timing is: (5-5-5-15) The new RAM is: DDR2 - 1066. timing is: (6-6-6-18) It's all G. Skill, 4 GB of each. The mobo most certainly does take DDR2-1066. It's written all over the mobo box. I never had to adjsut any timings or anything for the DDR2-800 RAM, it jsut worked out of the box. This time, the computer is not liking the DDR2-1066 RAM at all. It won't start. It gets power, but it just kinda fades in and out, and does not boot. So does it sound like it's bad RAM, or maybe just something needs to be adjusted for the timing? I am not an overclocking type, and would just as soon not mess with timings or voltages, unless I have to mess with the timing to get it to work on my system! Thanks!