Well I'm running a 670 and 3770K on a 360x60 Phobya G-Changer v1.2. Granted, the chip is at a ridiculously low voltage for the clock, but considering how hot they like to get, I've been more than happy. In this hot summer, it's run up to about 60*C across the board on its own and about 68 with FurMark running alongside prime. Graphics runs at about 50*C under that load.
The 240x80 is by no means a bad option, however you'd always be better off with increased fan area, as if we assume the same transfer volume, you'll get more airflow with less noise that way. Also, price comes to mind, you might be able to find a 360x60 cheaper, I'm not sure, I've not looked in a while.
If you can fit a 360 Monsta - go for it, stick a set of quiet edition Corsair SP120s on it, or if you like - NF-F12s (if you can find them cheap enough that is), and you shouldn't have much of an issue getting the temps you want. That gives you the option of later adding things into your loop, like more powerful graphics cards, or moving your CPU into it too. If you run a rad that big with the SP120QEs you can stick the low noise adapters on them and they become whisper quiet
In any case, for the sake of simplicity you want to keep to a single radiator and go with the biggest that will fit/you can afford.
I don't think a D5 pump would be necessary for two graphics cards, considering it will be a simple loop, but I guess it doesn't hurt to have an overhead just in case.
My personal choice of thermal grease has been for a while and mostly remains Arctic Silver 5. Now, bare in mind, it is capacitive and WILL kill anything electrical it comes into contact with, you also need to fiddle around with it a fair bit until you can get the most out of it without having to wait for the week and a half curing time, so instead I'd point you towards MX-4, which I hear is just as good if not better, and has none of the issues. IC Diamond is also good, unless you're mounting directly on the die, in which case you want to go with something non abrasive.
As far as I know, Tom's been quite happy with the Noctua NT-H1, so that's bound to be decent too.
My advice to you would be to stick a blob in the middle of the die or IHS, about the size of a grain of rice, and let it spread as you squeeze the water block on. This will ensure you get no air trapped between the contact surfaces, resulting in better heat transfer.
As long as the thermal grease isn't too viscous, it shouldn't be a problem to put a little bit more on so that you get full coverage (though unnecessary in my opinion). If you're running bare die, you want at least a bit to squeeze out of the sides, so that full coverage is guaranteed. What you don't want on a bare die is poor coverage, it might result in hot spots which kill your card (that is if the 580s don't have heat spreaders, if they do, you have nothing to worry about).
The size of hose is up to you, if you're going with a D5, it will handle smaller hose, but the general trend is 1/2"ID and 5/8"OD (inside and outside diameter). You will also need fittings to match. If you've seen Tom's water cooling guide, you'll remember what he does with 1/2" barbs and 7/16" hose.
Once you have your main parts together, try to visualise the loop and see where you'll need the barbs to go and how you can run your hose. Keeping the hose as short as possible ensures a tidy loop, reduces the amount of coolant it swallows up and also the resistance or back pressure you'd get from your loop.
You won't know what fittings you need until you start building ironically, and then, you might not be happy with something and end up not using some of the ones you ordered, so getting it within budget with minimum waste is a bit of a trick, but it's doable if you take your time. I'm pretty sure people who do this on a regular basis keep a steady supply of 45s and 90s at the very least. Obviously you and I can't do that, the fittings seem cheap at first, but the price quickly adds up. If you can do it tidily without shelling out on fittings - all the better. You might need a couple of 90s to hook up the blocks though, I'm assuming you want to stick that 240 Monsta in the front, along with the pump and res. I'm kind of jumping ahead here, but I see this with a 90 on the inlet and outlet of your GPU bridge, which you're better off running in series by the way, a hose going straight to the top side from the pump, then out the bottom and into one side of the radiator, then out the other and into the res inlet. You might need a 45 on the radiator inlet just to tidy it up a bit, so that's three fittings so far. Ideally, you want the radiator with the inlet and outlet at the top for easy bleeding, and come to think of it, might as well reverse the loop direction, so you go from pump to rad, blocks and back to res. This way, all the air would bleed out of the top of the radiator, enter the water blocks, then be forced to the top of the water blocks and come straight out into the res, which you can then top up with coolant. I did my sister's rig in a similar way (though she has her CPU on water instead), and it bled fully in minutes.
Come to think of it, you can mount the rad laying flat on the bottom, so that'd be even easier to bleed, but will need a 45 on the bottom of the GPU link and a 45 on one side of the rad. I'm sorry, I seem to be throwing ideas left right and centre here :crazy:, this is supposed to be your build ^_^
When it comes to coolant, you have plenty of options. Depending on what colour you want, any special effects, etc, you'd do well to have a look around. In general, you can't really go wrong with coolant they sell on Specialtech, it's one of the places where enthusiasts buy their gear and if it's not good - it won't sell, so they won't stock it. I'm currently using Mayhem's X1, but after the coolant fiasco around Orca, I defer judgement to Tom on this one, he should be able to point you better.
Oh, and before I forget, as it seems you're mounting this as intake, bare in mind that you will be dumping a lot of heat inside the case, so it's worth at one time or another to flip the fans on the H80 so they intake cold air. The last thing we want is the CPU getting hot because the graphics cards are now dumping all their heat in the case
Have I missed anything?
Ive got two of the Gainward 580's. & im crossing my fingers the waterblocks will fit straight on, as i've read, the EVGA cards were incompatible with their waterblocks due to heatspreaders.
, quite liked them too..... ) and/or, another case?
