Can I mix these RAM?

[tornpawn]

I have an EVGA NVIDIA nForce 680i SLI Motherboard with OCZ 2GB (2 x 1GB) 240-Pin DDR2 800 (PC2 6400) on it. I want to purchase more RAM but I am not sure if I can mix the RAM safely. I want at least 4GB of RAM and I was looking at buying Kingston DDR2 4GB PC8500 DUAL HYP RAM from Fry's for $49.99 that would give me 6GB of RAM. Would this give me any problems?

I have done several hours of reading on the web and found conflicting answers to this question. The voltage difference from the two different RAM kit gives me a great deal of worry, but I'm not sure if by default my motherboard would set the Kingston RAM to 1.8 volts. I would appreciate any feedback on this answer and if anyone can think of a better setup for me with the least amount of money that would also be helpful.

 

[badge]

To add another 2 x 1 GB kit, match the voltage timings and speed with what you have. There is no guarantee they will work together, trial and error. No use in buying the Kingston PC28500 which will default to the slower PC26400 speed. Also, PC28500 requires 2.0-2.1v where PC26400 requires less, 1.8-1.9v