4x on my last computer build

I have a few questions but first - this was my computer up until about two days ago when the PSU went and took the motherboard with it.

MSI 760GM-p35
ATI Radeon 4600 HD
AMD Phenome IIX4 955t Black Edition (running at about 4.2ghz)
4gb ram
win 7 64

Keep in mind - I used to be computer literate, but I didn't keep up with technology or terminology for a while - now I'm really behind and I don't really understand most of this stuff. (I remember when my commodore 64 was AWESOME.)

My first comment/concern - I ran 4x toons on this computer for about 3 months or so - main screen taking up 3/4 of the screen and the other three screens taking up the last 1/4. The only three settings I cared about set on ultra ultra (view distance stuff and spell effects) the rest were on low. The main screen ran just fine (30+ fps.PVP/raids) At the time I was using keyclone.

I switched to isboxer about a week ago and I was having some issues that I'd like to just see if I can have a general idea of how to fix before I re-install.

1) FPS dropped to like 25 idle and as low as 6 in combat on my main screen, even with all settings on low. This was on a fresh rebuild of the computer - pretty much all it had on it was WoW, VLC, chrome, and isboxer. Was set to dx9 with all the CCC settings as low as possible.
A) In ISboxer, is there a way to keep the main screen fullscreened (3/4 with 1/4 split) but have a lower resolution? The only way I could find to set resolution was to actually set the game into tiny windows. Keyclone has the maximizer thing - does ISboxer have something similar?

2) I'm looking to upgrade my GPU, but I'm on a very fixed budget - I was looking at http://www.newegg.com/Product/Produc...82E16814150560
Keeping in mind my setting requirements (viewdistance on ultra and particle density on ultra, all else on LOW) would this card work for me?

3) I ordered a bandaid MOBO http://www.newegg.com/Product/Produc...82E16813130634
I've had very good luck with MSI over the last 15 years, but like I said - bandaid.

4) I have new gskill memory (16gb) to throw in it.

Will this build be able to 4x? I'm not looking to break fps records or etc - just 30+ on the main screen with ISboxer, no AA, no extra special etc - just viewdistance and particle density up.

Thanks a ton!

1. Isboxer will allow instant swaps between running game instances. In order to do that it must render all game windows at the same resolution i.e. full screen (or 3/4 in your case). This puts extra load on your pc resources so plan accordingly. Use the window layout wizard to setup how you want the windows to go. It works well and you can adjust the the sizes if you like.

2. That card should be fine for 4 instances. I use the 6970 2gb card for running 5 and have lots of headroom. If you could squeeze a 68xx or 69xx in your budget that would help. The 1gb ram may be a limiting factor to turning up the visuals on the slaves.

3. MB looks fine to me.

4. Plenty of ram for 4 instances and back ground work at the same time.

Your setup should do window swapping just fine. Your fps will go up a lot with the new V-card. I think your limiting factor will be hard drive through put in busy areas when the details are turned up.

I welcome any corrections to my advice and defer to the hardware gurus at all times. :)