What's the best RAM configuration: 4GB @ 800MHz or 6GB @ 667MHz?
I've got a Windows 7 machine that at one time had 2GB RAM @ 800MHz. I bought an extra 4GB RAM that is PC2-6400, but when I added it to my existing 2GB, it defaulted the entire 6GB to 667MHz speeds.
I believe if I put in the 4GB RAM on its own, it will work at 800MHz, and if I put the 2GB RAM in on its own, it will work at 800MHz, but perhaps because of the different CAS Latency (the 2GB runs at CL5 @ 400MHz, but the 4GB runs at CL6) it won't do 800MHz when they're together.
So my question is - which is better? I'm asking this because it determines whether or not I "donate" the 2GB RAM from my computer to another computer I'm building, or whether I buy fresh RAM for the new computer... which leads me to deals.woot to look for a good deal on said fresh RAM.
Since you're probably wondering, I use the existing computer for general tasks and occasional power work (photo / video editing). How will each configuration affect my day to day performance?