3 logging 1 box?

I've had 2 accounts for a long time and used my 60s or now 70s to help my lowbies out via alt tabbing etc. So i finaly get around to it and start doing some reading, i find this place and what a wealth of knowledge it is. I read through the AHK threads last night and I got 2 locks going. I loving dinging levels at exactly the same time. So I just read Xjin saying that 3 toons is a major step over 2. Can I run 3 wows on one machine?

Hardware:
Opteron 144 (Oclocked to 2700 [sick processor])
2gigs of ram
FSB 1ghz
8800 GTS 640mb ram
Dell 24" wide

I don't think it'll be an issue as i get better and addons set up. Currently I have them in windowed mode, both open but one just open enough to see castbar and chat window (for the obligated whisper replies). So I'm thinking as i get better and a chat forwarding addon i could run the 2 totally minimized and 1 open. Your thoughts?

I run 3 windowed WoW sessions on my laptop with absolutely no problems. But I've also turned down all the graphics sliders (except the view distance one). Each one runs at about 1280x1024 and none of them are minimized. I get at least 40+ FPS in each window (although I can only see one at a time, since they all stack on each other).

Laptop has a Core 2 Duo, 2GB RAM and a 7950gtx mobile.

looks like i'm buying another warcraft box on my way home from work then. 3 locks or a priest and 2 locks? Shadow priest would be hot with the locks.