This is something i've never really understood. I used to just think that you buy the fastest ram that your motherboard/FSB can use. Over the last few years (for amd based boards) this went from 266 to 333 and now to 400. I have yet to see a motherboard that lists past 400 so i'm wondering what all these other types of ram that are faster than pc3200 are for. Does it just let you "overclock" easier since its rated faster? For example if i buy pc3500 ram instead of pc3200 does that mean i can clock my ram up to 433 easier whereas that speed might be unstable on pc3200? There's got to be something i'm missing here because otherwise why would anyone buy pc3200 when they could get faster ram for almost the same price?

With a lot of CPU chips being multiplier locked out of the box, raising the FSB was the easiest way to overclock & yes, that's when such memory comes in handy. Often enough you can get some good results out of PC3200 Ram if you raise its voltage a little bit & if you lower the timings.

Ram modules of speeds above PC3200 are simply hand-picked modules that have been tested to run reliably at more then 200mhz.

Ok but overclocking your fsb does more than just increase your cpu speed, it also speeds up your RAM which improves performance in itself, correct? So why wouldn't everyone just buy some ram rated at 500 mhz and clock it up that high?

Also, i've heard of loosening your memory timings to improve overclocks but why would you want to do that? In my experience, lower memory timings improve performance much more than a little overclocking.

Not everyone buys Ram faster then PC3200 because it is much more expensive & not everyone is into overclocking. & yes, lower timings are recommended for better performance but Ram running at 500mhz with timings set to 3-3-3-6 will still be much faster then Ram running at 400mhz with 2-2-2-5 timings.

Fater RAM for better CPU's like the Athlon 64, the RAM runs in time with the CPU so if you have 333 bus CPU with PC 3200 it will undeclock to PC 2700 because of the CPU.