Radiator Overkill ?

[momo56]

So basically I have 3 thermochill pa120.3 radiators. Would it make much of a significant temperature difference between 1 or 2 loops? My one loop would be:

CPU > 2 Mosfets > NB SB > GPU> 3 rads > res > pump

or my 2 loops would be

CPU > 2 mosfets > 2 rads > res > pump
NB SB > GPU > rad > res > pump

The 3 rads would be aligned horizontally with water coming in from the top port and out of the bottom.

My dilemma is that 1 loop would make everything look much neater as the zalman gt1000 case can get quite cramped but I want to overclock the i7 920 and 4870 X2 to decent levels so I may need 2 loops which will cost more.

Surely it wouldnt make much difference if I had 3 rads ? Considering sound wouldn't be an issue when gaming.

 

[JonJ678]

The general consensus is that two loops, specifically isolating the graphics cards from the rest of the system, is better. This is because the graphics card can (generally) tolerate significantly higher temperatures than the rest of the components. As such you make the most of the available radiator surface area. I strongly suspect, though have not checked the wattages involved, that a single PA120.3 is overspecified for your graphics card.

A single PA120.3 will give better than average performance for the rest of the components. Expect cpu temperatures about 20 degrees over water temperatures, and water temps of about 6 over ambient for this set up. A second radiator will halve the water-air difference but not change the cpu-water difference. As such radiators present diminishing returns pretty quickly once the water is less than ten degrees above air temp, and you may find yourself obsessing over thermal paste instead. Of course, if you double the number of radiators, you can run the fans slower...

If I could fit three triple 120's in my case I'd have them (happily), and my computer is probably dumping about the same heat into the water as yours will*. As it happens, the best I can do is three single 120's and one double. Temperatures were pretty good in winter but really suck right now. One triple isn't going to be enough for you, but two should be slightly over what's required.

I personally dislike the idea of multiple loops. However I've currently got four water blocks, four radiators and two pumps in a single loop; it's not performing terribly well and it's ridiculous amounts of hassle to change things around. Not recommended! (I was also told that everything in one loop is a bad plan, and ignored this advice, so I sympathise if you want to try it anyway).

The pump normally recommended for multiple block loops is the 18W ddc. It won't be enough to offer good performance with the first suggested layout. You'll need two of them in series. At which point, you may as well go for two loops. Assuming that the tdp of a 4870x2, when overclocked, is under 300W or so, you can seriously consider a single reservoir system. The flow will remain largely independent, i.e. mixing in the reservoir will be limited. However it is more compact, and indeed neater. Especially appealing here is the bay reservoir that takes two laing ddc's. Can't remember offhand who makes it, but it's probably xspc.

If you're really indifferent about sound, you can probably make do with just one radiator

*Two 8800gt's, 20% overclock, 920 @ 4ghz using a measured 370W. At least some of the waste heat from the psu is also being dumped into the water, though I don't know how much