New to watercooling GPUs: Before CPU in loop? After? SLI?

[CZroe]

At launch last year I bought a GTX 760 with the intention of upgrading to SLi and watercooling in the future. I read that, in SLi, it would be better than GTX Titan performance for a fraction of the cost, so I made sure to get the 4GB version specifically. I also made sure to get one with a reference cooler because I thought it would be easier to pair in SLi later and match up with a waterblock. As it turns out, most 760 cards with enhanced cooling use the GTX 680/780/Titan PCBs (waterblocks for those are much easier to come by & cheaper) while mine is the same short PCB as the GTX 670. Most GTX 670 waterblocks have been discontinued, but at least they exist.

It doesn't help that EVGA discontinued my model (04G-P4-2766-KR) almost immediately thanks to reference non-OC cards not being too popular. I still intend to find an identical card for my brother to run in his mini-ITX system until he is ready to upgrade, but we both plan to get the watercooling going now and I need to plan for their future use in SLi. This is where I am clueless.

I don't even know the first thing about tying a GPU into the loop. My system has a Swiftech H320 in a custom chassis and my brother's has a Swiftech H220 in a mini-ITX nCase M1. We are both running Haswell K-series CPUs. Should we be putting the GPU in the loop before or after the CPU? Does the answer to this change when I move up to SLi? What are these manufacturer-specific SLi accessories each waterblock option seems to have? What do those even do, exactly? Split the flow with equal pressure? Can I get away without them? If we get two different waterblock brands will I be able to mix and match them in the SLi system? After looking at prices, I'm tempted to just get an Asetek AIO cooler with that $30 bracket from NZXT!

 

[Tweakin]

At launch last year I bought a GTX 760 with the intention of upgrading to SLi and watercooling in the future. I read that, in SLi, it would be better than GTX Titan performance for a fraction of the cost, so I made sure to get the 4GB version specifically. I also made sure to get one with a reference cooler because I thought it would be easier to pair in SLi later and match up with a waterblock. As it turns out, most 760 cards with enhanced cooling use the GTX 680/780/Titan PCBs (waterblocks for those are much easier to come by & cheaper) while mine is the same short PCB as the GTX 670. Most GTX 670 waterblocks have been discontinued, but at least they exist.

It doesn't help that EVGA discontinued my model (04G-P4-2766-KR) almost immediately thanks to reference non-OC cards not being too popular. I still intend to find an identical card for my brother to run in his mini-ITX system until he is ready to upgrade, but we both plan to get the watercooling going now and I need to plan for their future use in SLi. This is where I am clueless.

I don't even know the first thing about tying a GPU into the loop. My system has a Swiftech H320 in a custom chassis and my brother's has a Swiftech H220 in a mini-ITX nCase M1. We are both running Haswell K-series CPUs. Should we be putting the GPU in the loop before or after the CPU? Does the answer to this change when I move up to SLi? What are these manufacturer-specific SLi accessories each waterblock option seems to have? What do those even do, exactly? Split the flow with equal pressure? Can I get away without them? If we get two different waterblock brands will I be able to mix and match them in the SLi system? After looking at prices, I'm tempted to just get an Asetek AIO cooler with that $30 bracket from NZXT!

With regards to 760's in sli beating a 780Titan...that's not going to happen. You would roughly be at or above a plain 780...I have 760's currently in sli.

Now, with regards to your placement in the loop, the difference between the water temp delta is minimal, so I would recommend that you lay out your loop as efficiently as possible, eliminating any drastic and unnecessary 90 degree bends. I run my as follows:

RES to PUMP
PUMP to 760#1
760#1 to 760#2
760#2 to CPU
CPU to RAD (small)
RAD to RAD (Large)
RAD to RES

Hope that helps to get you started. I would also recommend you visit Martins Liquid Lab and use this as a reference.

 

[CZroe]

With regards to 760's in sli beating a 780Titan...that's not going to happen. You would roughly be at or above a plain 780...I have 760's currently in sli.

Now, with regards to your placement in the loop, the difference between the water temp delta is minimal, so I would recommend that you lay out your loop as efficiently as possible, eliminating any drastic and unnecessary 90 degree bends. I run my as follows:

RES to PUMP
PUMP to 760#1
760#1 to 760#2
760#2 to CPU
CPU to RAD (small)
RAD to RAD (Large)
RAD to RES

Hope that helps to get you started. I would also recommend you visit Martins Liquid Lab and use this as a reference.

Thanks. It looks like I've got a lot of reading to do!

780 Titan? I'm actually talking about the Titan that predates both the 760 and 780:
http://www.forbes.com/sites/jasonev...l-269-nvidia-gtx-760s-outperform-a-999-titan/

I do intend to OC as far as possible.

What waterblocks are you running for your GTX 760 SLi setup? Short or long PCB?

 

[Tweakin]

Thanks. It looks like I've got a lot of reading to do!

780 Titan? I'm actually talking about the Titan that predates both the 760 and 780:
http://www.forbes.com/sites/jasonev...l-269-nvidia-gtx-760s-outperform-a-999-titan/

I do intend to OC as far as possible.

What waterblocks are you running for your GTX 760 SLi setup? Short or long PCB?

I have them configure with alphacool NexXxoS full waterblocks with backplates as seen here.

 

[CZroe]

I have them configure with alphacool NexXxoS full waterblocks with backplates as seen here.

Yours must be the longer reference PCB (680, 770, 780, etc). It looks like their short PCB version is cheaper to import on eBay than any others I can find here so I'm watching those on eBay.

 

[Tweakin]

Yours must be the longer reference PCB (680, 770, 780, etc). It looks like their short PCB version is cheaper to import on eBay than any others I can find here so I'm watching those on eBay.

Correct, I have the nVidia reference board.

 

[Aikouka]

The Swiftech unit that you have is only a 3x120 setup if I remember correctly. That most likely won't be sufficient for handling a CPU and two GPUs at full load.

Should we be putting the GPU in the loop before or after the CPU?

As Tweakin said, the order doesn't really matter. The general rule for laying out a loop is to try to keep the tubes as short as you can.

What are these manufacturer-specific SLi accessories each waterblock option seems to have? What do those even do, exactly? Split the flow with equal pressure? Can I get away without them? If we get two different waterblock brands will I be able to mix and match them in the SLi system?

The accessories make multiple GPUs considerably easier to hook up. Honestly, the thought of trying to hook up a super small tubing run sounds rather awful. When I did water cooling, I used a Heatkiller GPU-X3 adapter with my Heatkiller blocks. In the SLI adapter that I used, the flow was parallel, and I think most work that way.

You can always mix the GPU blocks, but you can't necessarily use one of those nice adapters. The problem is that the position of the inlets/outlets is different or the connection method might be completely different. I would probably recommend getting the same block.

After looking at prices, I'm tempted to just get an Asetek AIO cooler with that $30 bracket from NZXT!

Water cooling isn't cheap! But if you want to save some money, I still have an EVGA GTX 780 with a factory water cooler to sell! I keep procrastinating putting it up for sale.

 

[aigomorla]

Id say cpu before gpu.. or gpu before cpu really depends on how much heat load you are running and at approximate what kind of flow.

Also what type of CPU you have and what its overclocked at.

Its a simple numbers game.
It takes roughly 350W moving at 1gpm for water temp to increase 1C.

So that means as water travels down your loop, everytime it hits a 350W heat source, it will increase 1C.

In most sli setups, 350W heat sources are there, however in some CPU setups its not.
This means in most cases in SLI setups, the water temp will increase 1C before it got to your cpu if the SLI cards were before the cpu.

However if placed the other way around, the water temps will increase 1C before it got to your second SLI card, making your Card temps uneven.

So back to my original statement, it really depends on what your aiming for.
Do you want the best GPU temps, or CPU temps.
Are you a heavy gamer? or a moderate one?
And How much flow are you running in the system...

 

[CZroe]

The Swiftech unit that you have is only a 3x120 setup if I remember correctly. That most likely won't be sufficient for handling a CPU and two GPUs at full load.



As Tweakin said, the order doesn't really matter. The general rule for laying out a loop is to try to keep the tubes as short as you can.



The accessories make multiple GPUs considerably easier to hook up. Honestly, the thought of trying to hook up a super small tubing run sounds rather awful. When I did water cooling, I used a Heatkiller GPU-X3 adapter with my Heatkiller blocks. In the SLI adapter that I used, the flow was parallel, and I think most work that way.

You can always mix the GPU blocks, but you can't necessarily use one of those nice adapters. The problem is that the position of the inlets/outlets is different or the connection method might be completely different. I would probably recommend getting the same block.



Water cooling isn't cheap! But if you want to save some money, I still have an EVGA GTX 780 with a factory water cooler to sell! I keep procrastinating putting it up for sale.

Thanks.
From my research is seems that the Swiftech H320 is more than capable. In testing, the H220 with stock fans outperformed every 240mm AIO kit regardless of what fans the others were tested with and they encourage you to throw a GPU in the loop for that. It even outperforms the 280mm AIO kits it was tested against. If the R9 295x2 can get by with a single-fan radiator, then the extra 120mm on the 320 should b able to handle this. If not, the pump can handle another radiator.

My brother may be interested in that 780 if the price is right.

 

[Tweakin]

...This means in most cases in SLI setups, the water temp will increase 1C before it got to your cpu if the SLI cards were before the cpu...

Aigo is right on. As I had ample rad space, I wasn't too concerned with the "load" temps. Fully loaded GPU benches would raise my cpu temp 1-2c, while the delta between the two gpu's was 2c. I also ran them in series.

 

[CZroe]

Correct, I have the nVidia reference board.

Well, if it's the longer one it's technically not reference for the 760 but it is reference for the 680. What cards do you have, exactly? I'm now looking for a 4GB 760 on a 680 reference PCB though I'm not sure it exists.

 

[Tweakin]

Well, if it's the longer one it's technically not reference for the 760 but it is reference for the 680. What cards do you have, exactly? I'm now looking for a 4GB 760 on a 680 reference PCB though I'm not sure it exists.

EVGA GTX-760 2GB w/ACX cooler. The alphacools only fit on reference boards, be it longer or shorter, I have no idea.

 

[CZroe]

EVGA GTX-760 2GB w/ACX cooler. The alphacools only fit on reference boards, be it longer or shorter, I have no idea.

Thanks. The shorter reference board has two 6-pin PCIe power connectors and the longer one has an 8 and a 6-pin PCIe connector.