I am having some trouble with the RAM on my system. My motherboard is ASrock 939 Dual SATA-II and I have 1280mb of RAM (2x512 and 1x256). No matter how many memory sticks I put in, it never runs higher than DDR266 even when I just put in one or 2 of the 512s which are DDR400. I set the memory speed to DDR400 on the MoBo settings and when I boot, CPU-Z shows that the memory is running at 133mhz. Also, when I set it to anything other than DDR400 on the BIOS, CPU-Z reports that the memory is running at DDR200 speeds... (PC1600). The speeds of my three memory sticks are as follows: 512 MB DDR400 512 MB DDR400 256 MB DDR266 However, the system still maxes out at only DDR266 even when the 256 stick is out of the mobo. It even does that when I use either one of the 512s alone... does anyone know what's going on?