[Solved] Mix two brands/sizes of RAM

I have GeIL Esoteria 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model GX24GB6400ERBPDC installed on windows 7 machine. EVGA i680 MB. I have an additional Crucial Ballistix 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model BL2KIT12864AA804. When I install the Crucial in the MB it posts fine, even memory test from MB comes out ok. But when I boot Windows 7 each time I get the BSOD. I've read on the boards that as long as the speed is the same (DDR2) I should have no problems. How can my MB work fine/recognize both sets of memory but WIN7 balks? Is there anything I can do to use the additional memory? Thanks in advance.

On my MB I selected auto for both voltage and timing. Shouldn't that adjust/suffice for all modules or should I manually tweak the voltage and timing. I don't want to burn out the memory or MB or anything else by doing this.

Dude, thanks a lot. I increased the voltage to 2.2v and wa la it worked. I also set the timings to 4-4-4-12 2t, they had been on auto registering at 5-5-5-18 2t. If I have any problems I'll go back to auto for the timings. I almost threw away 2GB of RAM! Thanks again!!