i can't seem to use my 1gb GEIL pc6400 at full 800mhz, the system crashes down every time i try to set it up to 800hmz or auto, it only works on 533mhz or 667mhz. my board is ECS-P965T can someone help me how can i set up the BIOS correctly?
I am not familiar with your RAM or motherboard, but it sounds like you have either a Vdimm or timing problem when using AUTO or 800. Find out what voltage your RAM is rated for (nominal not max), and set Vdimm to that. Also find out what the timings are for your RAM at DDR 800 and manually set them. Hopefully this will clear it up. If it doesn't try relaxing the timings a bit from their published values. Many P965 boards have a very low starting Vdimm by default, infact many boards refused to POST with some OCZ RAM for this very reason. You may also want to check to see if a newer BIOS revision is available for your motherboard, this may clear up any incompatibilities with your RAM.
When you say crashes, do you mean doesn't POST, or you can't get to into your OS, or once in the OS it crashes after sometime?
i've already manually set it up to 5-5-5-15 as indicated in the ram itself. the voltage for my ram is 1.8V, it does post, but when it comes to loading xp it crashes.and there were no update for the board. and the board doesn't have a over clocking features.
Try upping the voltage to the next notch (probably 1.9V), also knock tras back to 18 rather than 15. I would also run Memtest, it can be downloaded HERE. It is a bootable (CD/Floppy depending on what you download) program that will run checks on your RAM. Let it run for a few hours, sometimes it takes awhile for errors to show up. If you don't get any errors say overnight, then you can rule out problems with your RAM. Try it at 800 if you can get it somewhat stable, otherwise run it at 667. Let us know how it goes.