360 rad enough to cool OCed i7 920, 2 GTX 480s and MB?

[MiSP]

I am currently building my first "real" watercooled rig, so I'm terribly sorry if these questions seem stupid to more experienced users. I have almost everything at hand now - just waiting for my three radiator fans to arrive.

This is my system (case and watercooled parts):

• Corsair 800D
• Core i7 920 @ 4GHz
• 2 GTX 480 SLI
• Asus P6T Deluxe v2

This is my watercooling setup:

• Feser (TFC) Xchanger 360
• 3 Noctua NF-P12 fans
• Laing DDC 18w (Swiftech MCP355) with XSPC res top
• EK waterblocks for all components mentioned above (for the MB: full cover + 2 mosfet blocks)

Now, I realize some of you may be hardcore watercooling users. I am not, and I don't expect my system to run with temps just above room temperature. However, I wonder if the watercooling system mentioned above is enough to allow an 4GHz overclock on the 920, as well as running everything within safe temperatures. I initially thought it would, but have since begun doubting this. What do you experts say?

If I have to upgrade, I was thinking of adding two single 120 radiators in a separate loop for the CPU (at the exterior/interior back and interior bottom of case), and everything else (GPU and MB) on the Feser 360. (I could have the MB in the CPU loop, but I will not OC the GPUs, and they normally operate under higher temps than the other components anyway, so I figured having them together with the MB blocks will be fine.) This means purchasing two new 120mm radiators (or preferably 140mm actually, but I haven't seen many of those), another identical pump, probably a dual XSPC res, and two more NF-PF12s. I do not want to casemod, as I'm not quite the handyman and do not have any tools for drilling or cutting.

To summarize, I would be very grateful for your opinion on these three setups (for the use described above):

• Everything (CPU, GPUs, MB) in a single loop using a single 360 rad at the top
• Everything in a single loop as above, but with two single 120mm rads between the CPU and the rest - probably a bit too much for the pump?
• Two separate loops - one for the CPU using two 120mm rads, and one for the rest (MB and GPU) using the 360 rad

Of course the latter would be recommended given unlimited funds, but could I make do with the former?

And of course, any other suggestions and input is highly welcome!

[arkon]

Crikey! That's a lot of heat being dumped into one loop!

I'm about to build a similar setup (with a 980X, and two GTX480s) - BTW, are you using the EVGA pre-fitted waterblock GTX480 "FTW" cards? How are you setting them up for SLI (by switching around the barbs?). Can you post a picture of your layout? Edit: Ah - just read, you said you were using after-market EK blocks for the GTXs? Make sure your power supply is beefy enough for all that kit! I'm going for the Silverstone 1500W 80plus-silver PSU - it hits its sweet spot at about 800W load...

I'm going to use a separate loop for the gfx cards - now I'm thinking of going for two, I'm definitely going for a quad-rad... these things are HOT, and you'd have to have some meaty fans to get enough air through a 360 rad with all that in your loop... (I know it must be cold in Norway, but I doubt you live in an igloo... your ambient temps will have to be quite low.) If you don't mind a high (say 10 deg C) deltaT (water temp - ambient air in) and 2000+RPM fans, you probably could - at a push - deal with that (would be very noisy).

Check out Skinnee Labs to see the charts of amount of heat dissipated from various radiators and fan combinations and speeds. I'm not sure, but a conservative estimate (judging by how much power these GTX480s use at full burn) would put them dumping 2 x 300W == 600W of heat into your loop... Then add 200-300W (is that right? ) dumped in by your O/Ced 920, it's getting up there...

As CPUs are a little more sensitive to running temps, I'd definitely go for a dual loop system. Check out my build list (now adding another GTX480 into the mix, if I can get my hands on one) - I've also plumped for the XSPC dual bay dual loop res. I was going for a more flexible system that could be tuned down for quiet operation as well, but cranked up for serious O/Cing.

So I'd go for your third option: two separate loops - but I'd stick the MB blocks in the CPU loop...

BTW, in your second option:

Everything in a single loop as above, but with two single 120mm rads between the CPU and the rest - probably a bit too much for the pump?

..it doesn't matter where you stick your rads in the loop (i.e. before/after/between components) - the water will quickly reach thermal equilibrium, so positions of components will make no significant difference to their temps.

Let us know how your build goes!

ATB,

4rkon

[MiSP]

Thanks! I've made quite some progress on a few other forums, and decided I will go for a dual loop, 360 or 408 rad on the GPU loop, 360 on the CPU+MB loop.

[MiSP]

New question: Do I (with 360 rad and 480 rad as described above) need to worry about water temps? Will I have to install temp probes? I really don't want to spend money on it if it's not necessary, as I already bought a fan controller (without temps).

[arkon]

Yes, I noticed your cross-post on another forum. Glad you're getting some answers!

I wouldn't worry about the water temps, especially once you've properly spec'd your setup. If you know you've got adequate heat dissipation etc. then there isn't much point IMHO - unless you are a hardcore w/c junkie! I thought about putting some in, but didn't want to restrict the flow of water through the loop (the probes will restrict the flow somewhat I think). Not worth it.

Also, remember that you can monitor your CPU and GPU temps - these are the most important ones to keep tabs on! If your CPU gets too hot, it will reduce its lifetime, and also will start to throttle down (SpeedStep/Overheat protection gubbins) so you'll noticeably lose performance. Run Prime95 on all four cores simultaneously and watch those temps rise! See where the temp stabilises - hopefully around 40 - 60 deg C... too close to 90 deg C and you're in trouble!

The GTX480 GPUs were designed to run hot, so they can handle it (and anyway, there are reports of a watercooled GTX480 running at only ~45-55 deg C, as opposed to ~100 deg C on air!!!). So plenty of headroom there I think.

Please do post a build log, as I'd be interested to see how your build goes, especially as I want to try out w/cing two GTX480s in SLI! (What other forums do you go on?)

Best of luck

4rkon

[MiSP]

I posted the same question on overclock.net (fattest thread), tech-forums.net, Extreme Overclocking, Chilled PC and Silent PC Review. Gotta make use of all resources.

As for a build log, don't know exactly what you mean. I won't make a worklog in the usual sense, at least. I'll get back on temps and results in all of the threads, and note if anything went particularly well/wrong during building.

[arkon]

Would like to see a picture of your final build, showing off your tubing for the SLI etc.!

4rkon

[MiSP]

Sure thing. I'll post final pics when I'm done, and guess what, I decided to make a mini-worklog (single post) too. (I mean, you can't drill through a stuck screw on the GTX 480 and not tell anyone about it!)

[MiSP]

Finally finished, worklog and temps here.