Hi all,
I have a little brain teaser here, I have a ASUS P5W-DH with a intell Quad core 6600, antec true power 650 watt psu, latest asus bios applied,

firstly I installed 2 crucial ballistix 8500 dims, bios dont auto detect correct speed, so I set it mamually, and everything was fine. anyway then I decided to upgrade my op system to windows ultimate 64 bit, still every thing is ok.

the problem starts when I then added another 2 gb of crucial ballistix same speed as others giving me a total of 4 gig.

what happens now is reboots or blue screen, the pairs are different batches, but crucial, assuure me they are the same density and are compatable.

They will run stable at PC7100 SETTING, so why not 8500? yet stable as pairs, even if I mix batch numbers, 3 will run ok, I am thinking voltage's have tried 1.95-1.80-2.0-2.05-2.2 and 2.15 to no avail, anyone had similar problems.

2GB kit (1GBx2), Ballistix 240-pin DIMM, DDR2 PC2-8500 memory module
BL2KIT12864AA1065






Module Size: 2GB kit (1GBx2)
Package: Ballistix 240-pin DIMM
Feature: DDR2 PC2-8500
Specs: DDR2 PC2-8500 • 5-5-5-15 • Unbuffered • NON-ECC • DDR2-1066 • 2.2V • 128Meg x 64