Water cooling Question re adding SLI to existing loop

[Siskods9]

I’m hoping someone knowledgeable in Water-Cooling can help me out with a little advice... (I am a WC newbie)

So I have my CPU (i7 3930k) overclocked to 4.7GHz using the Swiftech H20-320 Edge HD kit
http://www.swiftech.com/h2o-x20-edge-hd.aspx
http://www.swiftech.com/h2o-x20-edge-hd.aspx#tab2

I’m using all 1/2” ID tubing, there is nothing else in my loop and I have the Swiftech kit mounted externally at the back of my Corsair 600T case using a rad box.

However I would now like to water cool my Nvidia GTX 680 SLI setup.

My intention is to add the video cards to my existing loop, though I understand that adding my dual GPUs would be too much for my single 360 rad, so here’s my idea: I’d like to add a 240 rad into my loop and continue to use the existing integrated pump / reservoir that comes with the Swiftech H20-320 Edge HD kit because I don’t want to complicate things by buying a reservoir and stand alone pump for the new 240 rad and running a second dedicated loop...

The Integrated pump in my Swiftech kit is a MCP35X and can move 17.5 LPM.

I was planning to mount the new 240 rad on the inside of the roof of my Corsair 600T and continue using all ½” ID tubing. A 240 is the biggest rad I could use, there simply is no room inside the case for a 360. I haven’t decided if I would use 2x120 fans pushing or pulling (dependent on space inside the case) and I also wonder as to the depth of the 240 rad. Is a thicker rad necessarily better?

The intended new loop would be:

360 rad ->CPU @4.7GHz ->240 rad -> gtx 680 sli parallel (EK FC gtx 680 water-blocks + EK-FC sli link bridge Parallel water flow not serial) -> 360 rad

Would this work out for me?

Finally, any advice on the placement of QDCs (Quick disconnects) would be much appreciated.

Thanks so much for all your help and advice fellas...

 

[Tsumi]

Actually, dual 680s with the 3930k will not be more than that 360 can handle. A 360 radiator is generally enough for SLI/crossfire setups, and the 680s do not put out that much heat.

The 35X pump is more than sufficient.

Thicker usually is better, but doing push/pull with a thinner radiator is generally better than a thicker radiator in push or pull only.

Loop order does not matter. QDCs should be put on components you plan to change out often. Usually, these are the GPU and CPU blocks.

 

[Imitation]

I like rolling with more rad the better The 360 might be able to handle it but why not drop an extra few bucks and add that 240? I think I would. Your main cost will be the 680 blocks anyway.

Personally i'm not a huge fan of the quick DC fittings due to their restriction and price but if u want em go for it. I'd probly put em in the loop so you can disconnect it in the most functional place possible, likely as the lines go in and out of the case perhaps?

 

[Erasmus354]

Quick and dirty answer if you want to maintain good performance then you want to give ~150W of heat for every 120mm^2 of radiator area. You are pushing it putting for sure putting everything into one 360 radiator. What does this mean in practice? Well it means that your water temperatures will rise to account for the extra heat, and subsequently your chip temperatures will rise. (A radiator can dissipate more heat if the coolant is hotter)

So will it work with just a 360? Yes it almost certainly will. Will you get good temperatures? No, you are going to be approaching air cooling temperatures but your system should be much quieter than having those GPU fans blazing.

 

[FaRKle0079]

Finally, any advice on the placement of QDCs (Quick disconnects) would be much appreciated.

QD's are lifesavers. They make swapping components and diagnosing issues super easy. If running multiple cards that take up a lot of hand-working room you'll definitely want to be able to remove your GPUs to install things such as a new SATA cable. I put a set of QDs between all major components (QDs between CPU and GPU, GPU and reservoir/pump, between reservoir/pump and radiator, and between radiator and CPU).

Would this work out for me?

It'll work out fine.

You are pushing it putting for sure putting everything into one 360 radiator.

Unless he's folding/running his GPUs and CPU at 100% all the time he'll be fine with just the 360. Even if he was running everything maxed he'd be achieving levels slightly cooler than air (but quieter).

 

[Tsumi]

Ran two GTX 275's and a Phenom II x4 965 on a 2x120 Thermaltake + 1x120 Swiftech radiator. By the way, the Thermaltake is a pretty crappy radiator. My GPU temps were significantly lower than on air, and the whole system was significantly quieter than the stock air cooler.

 

[Erasmus354]

Unless he's folding/running his GPUs and CPU at 100% all the time he'll be fine with just the 360. Even if he was running everything maxed he'd be achieving levels slightly cooler than air (but quieter).

I'm sorry, but the data does not back up your assertion. He is putting a lot of heat into that loop. The Radiator he is using (In that kit it is the Swiftech MCR320-QP) is one of the worst 3x120mm radiators on the market currently. It ranked last in Martinsliquidlab.com testing of radiators only dissipating 244W while maintaining a 10C air to water temperature difference.

He is putting much more than 244W into his loop, hell his CPU is well over half of that with the overclock he is running. So what that means is his coolant temperature will necessarily have to rise to dissipate the additional heat. Hotter coolant means hotter processors. Simple physics.

 

[FaRKle0079]

I'm sorry, but the data does not back up your assertion. He is putting a lot of heat into that loop. The Radiator he is using (In that kit it is the Swiftech MCR320-QP) is one of the worst 3x120mm radiators on the market currently. It ranked last in Martinsliquidlab.com testing of radiators only dissipating 244W while maintaining a 10C air to water temperature difference.

He is putting much more than 244W into his loop, hell his CPU is well over half of that with the overclock he is running. So what that means is his coolant temperature will necessarily have to rise to dissipate the additional heat. Hotter coolant means hotter processors. Simple physics.

Funny how you can claim the MCR320 that "only" dissipates 244W @ 10C delta will be completely destroyed by his rig when the popular RX360 only dissipates 60W more in the same test and there are many users running that with OC'd CPU and SLI/CFX GPUs. Max TDP =/= power used while gaming.

WC is much more robust than you believe: CPU & GPU on a dual 92mm rad

 

[Tsumi]

Even if the delta is 10 C, as long as the temps are equivalent to or lower than air temps, and the system is a lot quieter, it's fine for his purposes.

 

[Ranma13]

I ran an i7 3770K and a GTX 670 on a thick 120mm rad with two undervolted push-pull fans in a mini-ITX case. Temps under Furmark + Prime95 at the same time were 90 C for the CPU and 77 C for the GPU. Temps under normal load (gaming) only got up to about 80 C for the CPU and 70 C for the GPU. All at stock speeds.

You may think that the temps are high, but they're well under the thermal limits. You may want it to be cooler if you're trying to achieve a high overclock, but for noise purposes, there really isn't any difference between a processor running at 50 C at load and 80 C at load.

Also, I don't really like these load tests that other people run. They either do it for the GPU only, or the CPU only, but not both. I'm a firm believer that if you want to find out what the maximum temp your computer gets to under load, stressing both the CPU and the GPU at the same time with the case doors (as opposed to an open air setup) is the only way to go.