5 boxing help in rift

Hoping someone can help me out. I'm trying to box 5 chars in rift. I have 2 installations of the game, one on a SSD and another on a usb 3.0 external drive. I've tried running all of them from one disk or splitting them between the 2, neither seems to help. I can run 3 fairly well, still lose a toon on follow occasionally though. Even with settings all the way down opening the 4th account drops me to under 10 fps...with 3 I usually get around 25 fps.

My question is whether upgrading my current comp will help or if running 2 or 3 computers would just be the best way to go. Currently I have an AMD 6200 processor running at 3.8. I tried to overclock, got to about 4.5 before my system kept crashing but it didn't help at all anyway. I also have 16 gigs of ram and a 680 video card. So if I put in an i7 proc will I be able to use one comp or does rift really require more than 1 comp to multibox? I'm also running Windows 7 ultimate 64. Is there any setting someone I can adjust to help, my proc does max out so I really don't think there is much I can do with current setup, but any suggestions would be appreciated.

Thank you

After getting ISboxer set up I'm running at about 25 fps with all 5 accounts up, graphics still all lowest...I was trying to use keyclone before. I thought ISboxer would be harsher on my system, but maybe the ability to actually use my 6 cores is helping alot? Would still appreciate any advice if there is any way to tweak it a bit better?

I have an i7 950 3Ghz machine with 2 580 GTX video cards. I use 2 machines to run rift. It seems to be a bit of a resource hog. In fact I have 4 accounts running on the i7 machine and running through Tempest Bay can still be a pain in the ass.

Yup, I'm running on an i7 950 with stock settings because I need to re-seat my CPU cooler, and the game can get pretty framey even at low settings. I've heard that there may be some optimizations coming to the game in the next major patch which I am hopeful for.