Originally Posted by mailman2
Your CPU will be a problem and especially with SLI. You are just further bottlenecking it. We've seen how CPU scaling with dual cards is very important. The faster the CPU the better.. so you can either try to overclock that further or may be looking at an upgrade.
I just went to an i7-860, newegg has a combo with an EVGA P55 LE for $422 that has another $30 MIR. I found a kit of DDR3 ram after rebate for $79. Basically after I sold my Q9550, 8GB DDR2 and motherboard it cost me about $15 to upgrade. It might be time to to the same.
You didn't mention your motherboard in your specs, but maybe you could get a Q9550 or 9560 to replace the Q6600 you have and drop it into your existing system even.
I think he's talking about his laptop.
EDIT: slaWter beat me to it.