Howdy I bought my parts and built a PC from Tiger direct. These are the specs. Pent Dual Core Quad 3.0ghz cpu
XFX nvidia 790i Ultra SLI mother board. Nvidia GEFORCE 9800 GX2 graphics card and 8gb ofCorsair 2048mb 1333MHZ. Creative Labs Sound Blaster X-Fi XtremeGamer PCI Sound Card, running on Windows Vista Home Premium 64 bit. Now here's my problem. When all 4 sticks of the memory are PUT in the computer after a bit I get freezing screen issues. The whole screen freezes and the sound repeats the last second over and over again when playing a game. I've taken the computer to tech heads and we've worked on it together. The computer will run fine with less then 8gb of memory WITHOUT freezing. I've replaced the memory with new memory right out of the package and have experienced the same problem when all 4 2048 sticks are placed in the motherboard. The motherboard was designed to hold up to 8gb of memory. So I'm thinking a voltage issue something like that. But to be honest I've never experienced it before. The computer has all the lastest drivers from Nvidia and their up to date also the sound card drivers are up to date for Vista 64 bit. Computer runs fine with 6gb or less down to 4gb. What do you think this might be? I am familiar with XP's blue screen for bad memory but this is a first. Thanks so much for wraping your brain around this. Check your MBoard manual for instructions on utilising all 8G of RAM...there may be a BIOS switch for this...
DLoad and run MemTest...let it run at least 2 hours...any errors at all and you have a bad stick of RAM.
You will need to test them one at a time to find the offending stick.See if this HELPS:

"For those familiar with the nForce 780i SLI, the board style mirrors this very closely, but there are a few key changes that have improved the layout quite considerably. Obviously the four DDR2 slots are now DDR3 – if you’re running above 1,600MHz though the two black slots need to be specifically used. This limits the use of the board to just a pair of DIMMs when you want to really crank it up (which is the whole point of the nForce 790i), so it seriously limits what you can currently do with it."

From here: http://www.bit-tech.net/hardware/2008/03/19/first_look_nvidia_nforce_790i_ultra_sli/4I'm using Corsair 4 sticks of 2048 1333 DDR3. I'm going try going into the bios and see if I can find out about the memory I seem to remember it having something about memory. Also where do I download memtest? Thanks guy for your help...www.memtest.org