DDR2 RAM 667mhz Vs 800mhz Question

Hello all. This is probably a very easy question to answer but I thought I'd ask just to make sure.

I am running Windows 7 (x86) on a desktop and have 2 gigs of Corsair DDR2 RAM (800mhz) installed. I also have a spare 2 gigs of cheaper DDR2 RAM running at only 667mhz. If I add the extra RAM am I right in thinking the faster RAM will run at 667mhz?

Is the performance boost of double RAM going to outweigh the loss in speed from 800mhz to 667mhz? Do you think it is worth adding the extra 2 gigs?

Many thanks. :)

You are correct that the memory will all run at the slowest speed of the bunch. You would barely notice a difference, outside of running benchmarks, with the slight drop in speed. If you can utilize the extra memory with the software you are running, then it is worth it.

However, there are two things to keep in mind. First, since you aren't running Windows 7 x64, you are likely only going to see about 3.25 GB in total. Second, anytime you mix and match memory, there is a chance they won't play nice together. The only way to know is to try them. As long as both sets are compatible with your board, you won't do any harm. If you start having random errors or lockups, then remove the slower sticks.

Thanks DeaconFrost. I'll install the extra RAM and see how it goes. Thanks for the reply.