Thread: RAM combination

I have an MSI P35 Neo3 motherboard, quad Core Q9650 processor, and 4 sticks of RAM w/c I recently upgraded (2 old Corsair 512 MB 667 MHz and 2 new Corsair 2GB 800MHz memory). My MSI MB is dual channel with 4 slots of memory supporting up to 8GB RAM. 2 of them is colored orange the other is green. The green slot is the one closest to my processor. I’m not really good on these stuff so now I am confused as to how to install these RAMs:

Is it ok to use all 4 RAMs even if capacity and speed are different for 512 and 2GB sticks? Will it affect my PC's performance? truth is, i don't want to get rid of the 2 512MB RAMs if they can boost my pc's performance up to 5GB RAM, but if they would affect the performance of the 2GB RAMs, I'd rather sell the old RAMs at a fair price =).

If yes, on which colored memory slot should I install the 512 or the 2GB memory (green or orange)?

If not, where do I insert the two pc 2GB RAMs, on the orange or the green slot?

If you can include a simple technical explanation as to why you arrived at your answer, it will be very much appreciated! I've been searching for answers over the net but would suggest different options and I get confused even more.

Please help.

All memory will run at 667 MHz, but you didn’t provide specs for the old and new modules. It doesn't matter what slot color you install them as long as identical modules are in same color slots, but do yourself a favor and sell the old modules. Unless you really need 5 GB, running slower memory will hurt performance a bit. I presume that you are running a 64-bit OS; otherwise running 4 GB or more is useless.