I'm looking to buy a new top-of-the-line system in August, but I'm not up to date on the latest in hardware considerations. I appreciate any advice on how to do about this. Specifically:

What vendors should I be looking at? Right now I'm looking at Alienware, but they only sell Intel chips, and I've heard that AMD chips perform significantly better at the same clock speed. But the fastest AMD chip they're sellling right now is 1.4ghz, and the fastest Intel chip is 1.7 or 1.8. So does the per-cycle advantage of the AMD overcome the raw speed of the Intel?

Any specific hardware should I be looking for? I know I'll be getting a GeForce 3. It looks like I've got no choice but to get a Soundblaster card.

What's the difference between SDRAM, Virtual Channel SDRAM, and RDRAM?