So I have a PC i've been using to 5 box for awhile. I keep reading about people having maxed out settings and running around WOW with a super computer, yet mine doesn't seem to measure up.

Q6600 quad, 2.4 ghz (Over clocked to 3.0)
4 Gig Ram
7200 RPM HD
8800 GT 512 meg video card
2 monitors 1 19" running my main toon and 1 22" running 4 alts
Graphics settings are at a minimum
Vista 32bit Ultimate
I let WOW autoselect the cores
I open all clients from 1 or 2 directories with about the same performance. (my biggest performance boost after i got this PC was opening wow from 2 directories instead of 5. I just haven't seen any large increases going from 2 to 1 though)

When I'm in the cities, it's hard to move around. Alterec Valley can get rather laggy too. When i'm out in an open area, i still can't have my 4 toons follow with epic flying mounts, i haven't used Crusader aura since I started 5 boxing.

I'm looking to upgrade this machine. What is the most likely culprit?

I'm about to get a 2nd 8800 GT 512 meg Video card and run my main from my 19" plugged into one card and let my 4 alts run on my 22" plugged into another card. Will this help at all?

I was asking around about a faster hard drive, and it seems only the server machines can run a harddisk at 10k rpm. Plus most people i talk to say it's more than likely not my hard disk.

If I decide I need a new CPU, is the intel 9450 or 6800 better for boxing? I only use this computer to play Wow. I might use it to open fraps and make videos, but the PC has no other use.

Lots of questions because I'm really confused about all this stuff.

Thanks in advance!