Originally Posted by go_sharks86
I looked in the RAM tutorial, but it only answered part of my question. Currently I have one gig of Corsair XMS RAM, specs are: 3200 (200mhz) and a CAS Latency of 3. What I want to know is if I buy a gig of RAM that has a CAS Latency of 2 or 2.5, will I run into any problems? Also, if I were to buy a different brand of RAM or a different type of Corsair RAM (ie something other than XMS), would I run into any problems?
Most of the time, no, you won't have any problem running CAS 2.5 or 2 at CAS 3. You are running it at a slower clock rate than it's rated for. Generally, you only have trouble running memory at a higher clock rate than it's made for. For example, trying to run CAS 3 RAM at 2.5 or 2.0 will often cause problems. Another part of the equation is voltage. CAS 2 or 2.5 memory might expect a higher voltage (set in the motherboard BIOS on most motherboards), but again, if you are underclocking it, you might not need to go as high as the recommended voltage. I recommend that you do.
Your RAM will all run at CAS 3, of course. The BIOS will set the system to run at the speed of the slowest chip.
Mixing brands generally doesn't cause problems either, but stick with well-tried name brands. Corsair, Crucial, Mushkin, OCZ, Kingston (not as much) in that order. I've also had good luck with Patriot Data Systems memory, but some people haven't.