black screeen help?

[newmodder]

ever once and a whilethe screen goes blank and some areas of the desktop are garrbled or i click on start or open vid card properties the screen flashes/goes black for 2-3 secs. any ideas. before i have to reinstall windows. or replace defecive hardware

[Aevum]

check PSU, sli setups suck alot of power,
test to see if you can reproduce problem with only one video card installed,
then test again with the other,
if problem dosnt occure with only one video card, psu issue or driver issue
if problem occures with one of the cards but not with the other (each one installed alone and tested individualy) that card is the problem.

problem occues with both cards when tested one at a time, driver/ram/motherboard problem.
cycle some memtest and prime95 to test hardware stability, preferably out of windows,
use ultimate boot CD, lets you test hardware without booting windows, so any error found, driver conflict is automaticly discarted as a possible cause.

another thing you should check is if both your cards are same brand and model, also check clock speeds, some 6600GT have 1.6ns and some have 2.0ns memory chips, this means that some can have above stock speeds,

some NF4 sli motherboards fix both cards at the speed of the first card, so put the slower first, and the faster will underclock, more stable, you loose some performance if you paid a premium to have a factory overclocked card, put the fast one first, the slower one will overclock, can cause instability, actually very probable,

[newmodder]

one of my cards died.getting a replacement tomorrow.