With 8GB of ram on a 32 bit OS he should still be seeing about 3gb which is more than enough to run 3 clients. I'd definitely suggest pulling the 2nd card out, depending on your mainboard the 2nd card could be throttled to 4 or 8 PCI-Express lanes instead of 16, which if someone sold you 8gb of ram and a 32bit OS then they likely didn't sell you a good mainboard... if you built and spec'd the system yourself it's quite possibly the cumulative noob mistakes killing you.

So from here I'd pull the 2nd card physically from the machine, see if your performance gets better. You may want to drop the memory down to 4gb and test it then. I doubt the extra 4gb would affect anything but it's possible.