I am building a new computer. So far for cooling I have two Black Ice SR-1 560 rads, 8 Noiseblocker PK-2 140mm fans, Aquerao 5XT, 3 PowerAdjust 2 Ultras, and 2 Aquastream Ultra pumps. I have an Asus Rampage IV Extreme X79 motherboard and will use an i7-3930K cpu. Original plan was two loops, one 560 rad, one Aquastream Ultra pump, one res for each loop. One loop to cool two EVGA 580 Classified Hydro Copper 3GB video cards and one loop to cool cpu, ram, and motherboard waterblock. Now I decided to go with 3 of these video cards. It seems my two loops are pretty lopsided as far as heat load.
Questions:
1. Should I continue with two loops as planned even though one loop has lots of heat input and the other does not or run one loop first to cpu then motherboard waterblock, then video cards so both 560 rads can cool the video cards?
2. Does one AquaStream Ultra pump have enough pressure and flow for one loop with two 560 rads, cpu block, motherboard block, and 3 video cards with waterblocks that are considred fairly restrictive?
3. Any other suggestions?

I think you're right about the single loop working better for me. I've figured out how I want to do the loop with two AquaStream Ultra XT pumps in series and have ordered fittings and tubing. From what I've seen online these pumps do pretty well in restrictive loops and since I am going through 3 EVGA Classified 580 HC cards and two SR-1 560 radiators I think my loop will be fairly restrictive. I will measure water temps at the pumps, after the first radiator, after the second radiator, after the CPU, and after the video cards. Looking forward to seeing what my temps will be.