I've got your total at $1208, is that right?
I'd suggest changing the HDD to either a Samsung Spinpoint F3 or Seagate Barracuda 1TB as they are just as fast, if not faster, while being quieter, cooler and cheaper.
Make sure that the voltage on the RAM is less than 1.65V, preferably 1.5V.
There is absolutely no need to get a 650W PSU, especially not if you're only going to use one 7850s. Frankly I would only recommend a 650W PSU for a system with CF 7850s if the user was going to heavily overclock both the CPU and the GPUs.
Oh ok, so do you think 550w would be sufficient instead? Or 600w or...i dunno lol
And this might sound stupid...but is RAM voltage something you can set afterwards or is it inherent with the kind of RAM you buy? So that one says it uses 1.65V...can i just lower to under to around 1.5V as you suggested?
Yes it is possible to change the voltage at which a set of RAM runs.
However the manufacturer has usually designed/tested the RAM to run at the voltage that is specified, so it is not guaranteed to be stable at a different/lower voltage.
Also the specified voltage is usually tied to the specified frequency, so it was tested at 1600MHz @ 1.65V. Hopefully you will be able to run it at 1600MHz @ 1.5V, but if it can't do that then it will do 1333MHz @ 1.5V, which it might actually default to anyway.
If that happens then maybe it would have been better to save some money by getting RAM specified to run at 1333MHz @ 1.5V.
The reason that the RAM voltage should be below 1.65V is because Intel states that voltage that high can cause damage to the integrated memory controller on the CPU. So if you're willing to take the chance/void the warranty then you could just run it at 1600MHz @ 1.65V.