Do,
Figure out what OC is your target by looking at other people's results.
Be realistic! Perhaps take an average of what you see, consider whether they have better CPU steppings, etc.
Whatever FSB you are shooting for in that overclock, you try to get RAM that will match that with a 1:1 ratio.
That ratio is FSB:RAM. Running 1:1 means they are running at the same speed, which is more efficient.
An example:
PC 3200 = DDR 400MHz. In other words it is guaranteed to run at 1:1 with a 200 FSB. (Since it is Double Data Rate, you divide 400MHz by 2. 200:200 == 1:1)
Most good brand RAM is overclockable to some degree, so usually you will be able to get it to run at a higher FSB than it is rated, it's just not
guaranteed by the manufacturer.
For instance I bought PC 3500 DDR 433MHz to run 1:1 with my target FSB of 216-217. Works great, but I could have probly got PC3200 and oc'ed it to 216.
I was (ok, I am) a noob and didn't want to take a chance on stability problems because I have to do my work on this box. For a gaming machine, you won't be losing income if you crash. Unless your games are online casino games maybe.
Sometimes when overclocking your RAM you may need to increase the VDIMM (voltage supplied to the RAM) and/or you may need to relax your timings so that it will be able to in keep up with your FSB while maintaining 1:1 ratio. By relaxing your timings I am referring to raising the CAS numbers of the RAM in the BIOS. They are numbers like 2.5-3-3-6. The lower the numbers the faster the RAM, and the more expensive. There is some insight into those numbers on the
Mushkin site, among other places. There is also a guide to overclocking your RAM somewhere. I am too lazy to look. If the jump in FSB is too much for the RAM to take at 1:1, like you are trying to run PC 2100 at 216 FSB, then you can run the ratio at 5:4, 4:3 or whatever, if your motherboard and BIOS support it.
Once you decide on a speed, you can try to find a particular stick. Good brands are Corsair, Mushkin, OCZ, Kingston, maybe Geil.
Look around to see if the brands you are thinking about have problems being compatible with that MB. Apparently some matchups don't like to overclock as well, or to work in dual channel as often, but some of that could be luck of the draw. The memory manufacturer web site may list the motherboards that it has been tested with, so that's be a good sign, but it doesn't rule out other boards. You can pay more for a "kit", 2 modules that have been tested together that are guaranteed to run in dual channel, but usually 2 of the same sticks will work just fine.
CAS 2.5 is generally the best for the money. You may not notice the difference between it and CAS 2. Now CAS2.5 Corsair Value Select PC3200 is ~ $77 for 512MB at newegg. So is Mushkin Green CAS 2.5. Others, dunno. You want a gig. Can you get it to run at the FSB you want? Newegg reviews may have some stats...
Go forth and multiply.