RAM FAQ

Speed
When it comes to buying ram, you need to keep a few things in mind. First of all, try to get the fastest memory your motherboard will support. Usually DDR2 800 is the fastest supported memory. Some newer motherboards can go up to DDR2 1200. (The absolute latest systems use DDR3, however, I would rather spend the extra cash on a second graphics card.)

Dual Channel
Buy it in pairs! If you buy two matching sticks, odds are your motherboard will run the memory in dual-channel-mode. Aka, it will be faster.

Low Latency
Does 'low latency' memory really make a difference? As far as more frames-per-second, probably not. However, take a look at the benchmark results below to decide for yourself if it's worth it.

4GB in Windows XP 32bit
Next, how much do you need? If you are running Windows XP 32bit, the maximum amount of memory your system will 'see' is 2.75GB (possibly up to 3.5GB depending on your hardware). This is due to the way Windows addresses devices in your system. It only has a certain amount of addressing space, and that space is shared with all the devices in your system, including the memory. Unfortunatley, it would appear that the engineers weren't invisioning systems utilizing over 2GB.

That being said, is it worth buying 4GB of memory even though Windows XP 32bit won't be able to use all of it? Technically, if you have all four of your memory slots filled, you will be running it in dual channel (if your sticks match).

Also consider this: The amount of memory shown in Windows is probably 2.75GB. That doesn't mean Windows is only using roughly 3 sticks of your memory, that 2.75GB is divided up 4 ways. So logically, there is more bandwith available... not to mention dual channel mode. Check out the chart below.

The chart above clearly shows an improvement when it comes to lower latencies and more memory. However, will you actually notice these differences? Honestly, probably not. 17.65GB/s vs 18.5GB/s... You will have to decide if it's worth it or not.

Benchmark System: E8400 3.0Ghz, Corsair XMS2 2GB - 4GB, 8800GTX, EVGA 780i