I built a system using the ASUS P4P800 board, 2.8 800mhz CPU and twin sticks of HyperX 3200. It was initially so unstable I sent one of the sticks back to Googlegear thinking it was bad. I just got a replacement and put it in. The system seems more stable than it did, but this morning it did a random re-boot on me, so I'm getting worried. Since I did the original install I've upgraded the BIOS to 1.007, so that may account for the increase in stability. I haven't fooled with the timing because I've never done it before and I'm not sure how you do it. (Is there a guide on THG somewhere?) Right now I have the RAM in slots 1 and 3 to take advantage of the Dual DDR400 boost. I'm wondering if I put them into slots 1 and 2 if the stability will increase. I know I'll lose the speed advantage of Dual DDR, but I don't know if it's a substantial difference in performance. Does anybody know? It doesn't matter how fast it is if it doesn't run without rebooting.