poor game performance

I am using ISBoxer program to box on world of warcraft. When I am just duel boxing the computer runs fine but when I run the third account I am having poor game performance. I have turned down the graphics on all three accounts, tried running a game booster, shut off addons , upgraded ram to 16 from 6, defragged, cleared cookies. I was wondering if a video card work help. Thanks for any advice in advance.

HOWTO: Tweak your framerate on the ISBoxer wiki provides advice on improving performance. The section on identifying bottlenecks sounds like it may be particularly relevant to you.

What is your current system?
Processor, Ram, Video Card, Hard Drive, etc...

What is your operating system?
Which version of Windows, is is 32-bit or 64-bit...

Thanks for the advice Alge, I worked it out and found what the problem was decided I needed to upgrade the power supply and a video card.