forumdude123 9 Posting Pro in Training

Hello guys, and here's a question i've been pondering lately. Ok, when building a desktop pc, will there be a difference in performance in speed if i choose 667mhz ram over 800mhz ram. The reason I am asking this is because i want to buy a cheap (but great quality) motherboard from asus that doesn't support 800mhz ram, and 800mhz ram is cheaper than 667mhz ram at the store i'm going to. I know that the memory will downclock it's self from 800 to 667, but i just don't know if it will be a source of degrading performance on my pc. Thanks for your support.

P.S. Also, should i buy 4gb of ram or 2gb of ram for my vista 32bit machine (don't tell me to buy 3gb, because it costs more than 4gb at the store i'm buying from. Here's the prices on the ram i'm talking about:

2gb- 34.99 after rebates
3gb- 99.99 after rebates
4gb- 64.99 after rebates

Thanks again for your support