Water cooling needed?
Water cooling needed?
I have a few questions about watercooling.
I’m budgeting around $3,000 for a custom system without the monitor. I’m considering an Intel 6800K or 6850K CPU with dual video cards using SLI Nvidia 1080 graphics. I plan to overclock and keep noise low.
I intend to purchase:
ASUS ROG SWIFT PG348Q 34" 3440x1440 IPS 100Hz G-SYNC Eye Care Gaming Monitor, plus a smaller 24-inch one.
I want to play games on Ultra with high frame rates.
My questions are:
1) Should I watercool the CPU, or is it enough to cool the GPU as well?
2) What impact does the CPU radiator size have—120, 240, or 360mm?
3) When using dual video cards, do they distribute the workload evenly, reducing heat compared to a single GPU? So maybe watercooling isn’t necessary?
4) Does the number of fans on the video cards matter?
Just a note - adding fans to your system will increase the number of fans, which can affect noise levels. Watercooling doesn't guarantee silence; it needs careful design to be quiet.
Not necessarily, but I suggest it if you desire silence and overclocking with dual GPUs.
240mm+ is recommended for CPU only, for 2 way-SLI 1080s and a 6800k I suggest at least a 360, preferably a 480 or dual 240s or dual 360s.
They will both run as hot as usual. Question 1 addresses the second part.
I would choose an EVGA FTW edition for watercooling since the blocks and parts are solid. STRIX from Asus is also a good option.
I advise purchasing an EK X360 or P360 kit and adding another radiator (along with your GPU blocks/backplate) and likely a second pump.
First, let me clarify that I personally don’t rely on water cooling for my systems.
1. No, there’s no significant gain in performance from water cooling for either the CPU or nVidia GPUs unless you’re aiming for extreme overclocking. Often, with today’s components, you encounter voltage limits or manufacturer restrictions before reaching temperature limits. Modern 1080 series CPUs begin to slow down around 82°C... for example, the MSI 1080 Gaming at full overclock reaches that temperature. If it stays below 82°C, it won’t throttle. Regardless of whether your GPU is at 81°C, 74°C or 40°C, the results will be identical. Water cooling mainly helps with noise reduction.
2. Installing a 120mm radiator on the CPU is unnecessary; a $30 air cooler will suffice. A CLC with a 240mm radiator on the CPU isn’t worth it.
3. They distribute the workload, but each unit handles more. One card can reach 74°C at 60 FPS, while two cards can max out at 72°C at 90 FPS. Except in real-world scenarios. Since the top card draws exhaust air from the bottom one, it can get up to 10°C hotter.
4. I haven’t encountered top-tier cards with just a single fan—usually two or three are better. Focus less on the details and more on size and sound quality. There’s no one-size-fits-all answer.
5. Sizing radiators mainly reflects the heat they generate. A 6800k overclocked chip draws about 125 watts; each 1080 produces roughly 200 watts from the box, plus an additional 20% (240 watts) for high-end models after boosting power to 120%.
So, considering these factors, we estimate around 625 watts total.
Experimentation shows radiators should manage about 60% of that load:
- 2 x 240 watts for the cards + 125 for the CPU + 20 watts for the pump = 375 watts.
Based on data sheets, we can assess how each radiator performs.
If noise isn’t a priority, opting for 1200 RPM fans is ideal—they operate silently below 850 RPM. For instance, the Alphacool XT45 (45mm thick) delivers about 83 watts per 140mm of radiator, which matches roughly 4.5 x 140mm for a 375-watt load.
A setup with 420mm radiator on top and 280mm on the bottom could provide about 415 watts, achieving an 8.3°C temperature difference.
Other configurations...
- Four 140mm radiators give ~11.3°C delta T.
- Three 140mm give ~15.1°C.
Using 120mm fans cuts cooling by ~25% (61 watts lost). Higher speeds still draw attention, but above 850 RPM they become noticeable.
Typical designs aim for a 10°C temperature drop. For SLI setups, a 420mm top radiator with 280mm bottom is common.
If you prefer custom loops, Swiftech H20 X2 with MSI GTX 1080 Seahawk EK is a solid choice.
I use:
- EK Supremacy CPU Block – [link]
- Swiftech Dual DDC MCP35X2 Pump – [link]
- EK Res 3 Reservoirs – [link]
- EK Full Cover Waterblocks – [link]
These components are pre-assembled, reliable, and avoid the issues seen with cheaper parts.
For the build:
I wasn’t overly impressed with the PG348Q. The G-Sync is fine, but without Motion Blur Reduction it’s hard to justify spending that much on a monitor. Until Display Port 1.4 monitors arrive, I haven’t recommended IPS screens above 1440p. There was a reported issue with the overdrive control in the TFTcentral review—its status is unclear.
2. With 1080s on the horizon, I’d wait for them or take advantage of their price once Ti is available.
3. Choosing between nVidia and Boost 3 models is tricky since they all perform similarly. Techpowerup rated them all highly (9.8), making it hard to pick one. Exceptions exist with certain EVGA models that still face VRM problems.
JackNaylorPE :
First of all let me start off by saying I water cool my personal systems.
1. No.... there is no longer any real performance improvement to be gained from water cooling either the CPU or nVidia GPUs unless you are into extreme overclocking. As often as not, with modern componentry, you hit the voltage wall or manufacturer imposed limits before you hit the temperature wall. Today's 1080s start to throttle at 82C ...here's the temp experienced by the MSI 1080 Gaming at max OC,
If the card hits 82C it's going to throttle, if it doesn't, it doesn't. So.... whether your GPU is at 81C, 74C or 40C, the card will perform exactly the same. What water cooling will do for you is reduce noise.
2. Using a 120mm radiator on a CPU is a waste of effort, a $30 air cooler will do just as well. Putting a CLC with a 240mm on your CPU might seem like a good idea ... It's NOT.
Start at the 17:12 mark @
https://www.youtube.com/watch?v=TivNOgQqW-M
The $100 Corsair H100i manages to keep the CPU at 73C at 4.4GHz ... but the $80 Noctua Air Cooler manages to keep it 2 degrees cooler ... and to lose by 2C, the H100i has to be 12 times as loud.
3. Yes, they split up the work load but they do more work .... 1 card may max out at 74C doing 60 fps but 2 cards will max out at 72C doing 90 fps. Except for "real life". Because the top card is using exhaust air from the bottom card as intake air, the top card may run as much as 10C hotter.
4. I haven't seen any top tier card with just one fan... it's usually 2 or 3. But don't focus on the minutia... size also matters ... sound also matters, so there is no universal answer.
Sizing radiators is strictly a measure of heat produced. An overclocked 6800k will produce about 125 watts.... each 1080 will produce about 200 watts outta the box, add 20% (240 watts) for the better cards after you raise the power limit to 120%
So .... 2 x 240 watts for the cards + 125 for the CPU 20 watts for the pump = 625 watts
Trough experimentation, we've learned that he rads need to handle about 60% of that load as a) there's never a condition where everything is at 100% b) it's an average not peak load that matters for cooling and c) your rad shrouds, heat sinks, backplates, and all component surfaces are radiating heat.
so 60% of 625 = 375 watts.
The typical design goal for a water cooled system is 10C delta T. Using the data sheets you can download here, we can see how each rad does in this respect
http://www.overclock.net/t/1457426/radia...-estimator
If you don't like noise, I'd suggest using 1200 rpm fans which will be dead silent below 850 rpm or so. Looking at the Alphacool XT45 (45mm thick), we see that each 140mm of rad provides about 83 watts of cooling (101 in push / pull. With a load of 375 watts, that works out to about 4.5 x 140mm.
Using say a 420mm rad on top and 280 on the bottom would give you 5 x 83 watts of cooling (415 watts) capability and I'd expect a Delta T of about 8.3C.
Other combinations...
4 x 140mm ... Delta T of 11.3
3 x 140mm ... Delta T of 15.1
Using 120mm fans will reduce your cooling by about 25% (61 watts per 120mm)
You can use higher speed fans but it defeats the purpose of water cooling... at 1800 rpm for example that XT45 will generate 117 watts of cooling per 140mm (41% increase) ... but again, you will hear the fans at anything above 850 or so rpm.
My typical water cooling design for a SLI system uses a 420mm (45mm thick) rad on top and 280mm (60mm thick) rad on bottom. If you find a custom loop a bit scary, consider using a Swiftech H20 X2 w/ twin MSI GTX 1080 Seahawk EK X .
I use:
EK Supremacy CPU Block -
https://www.ekwb.com/shop/water-blocks/cpu-blocks
Swiftech Dual DDC MCP35X2 Pump -
http://www.swiftech.com/MCP35x2PUMP.aspx
EK Res 3 Resrvoirs -
https://www.ekwb.com/shop/reservoirs/res...-x3-series
EK Full Cover Watewrblocks -
https://www.ekwb.com/shop/water-blocks/v...ia-geforce
The Swiftech is a pre-assembled set of custom water loop components which can be expanded to include additional blocks and rads very easily. Unlike CLCs, no cheap componentry, no aluminum rads, no mixed metals. The cards uses an EK full cover water block and the MSI cards are free from the issues that plague the EVGA SC and FTW lines tho to be fair, water cooling kinda solves those issues.
http://www.swiftech.com/h240x2.aspx
http://www.newegg.com/Product/Product.as...6814127952
You'll need to buy some extra fittings, tubing and coolant to connect the blocks.
As for the build ...
1. I was not all that impressed with the PG348Q. G-Sync is nice and all that but with no Motion Blur Reduction (ULMB) I really can't see paying that much for a monitor. Until Display Port 1.4 monitors arrive, I have not been recommending IPS screens above 1440p. There was a bug w/ the overdrive control mentioned in the TFTcentral review... i dunno if it was fixed yet
2. With the 1080s expected to drop soon, i think I'd be waiting for them either to get them or take advantage of the price of the 1080s once the Ti hits.
3. As for which 1080 to buy, nVidia and Boost 3 have made choosing somewhat hard as they all perform relatively the same. Techpowerup gave them all a 9.8 rating so it's hard to argue for one over the other....except for the EVGA models which are having the VRM issues.
Thanks for taking the time to respond. Lots of info here and a little bit overhelming. Im trying to make this simple and I like the idea of using the Swifttech H240 X2 (Prestige) with the dual MSI 1080's Seahawk EK X making it little simplier.
So how would you set it up in the loop? Alphacool XT45 (420mm) on top of case. Swifttech H240 X2 on the front, than what?
For example,
Swifttech rad/res/pump combo in front > top Alphacool > cpu block > gpu1 > gpu2 (in parallel) > back to Swifttech?
Specifically what extra fittings, tubing and coolant do I need and best place to get them? and 1200mm fans too
Can you recommend a great case to acommodate this set up?
thanks in advance..
I own an XT45-420 at the top and a UT60-280 inside an Enthoo Primo... it's a straightforward build but it's a very large case. The Enthoo Luxe should fit the X45-420 but can only accommodate a 240mm radius on the front as per the manual... so you'd likely need to use the H220 X2 Prestige.
Check the image for mounting instructions. The procedure is outlined on the right side of page 1. I don’t have an Enthoo Luxe case nearby, so I can’t measure it directly. Are you sure you’d need to remove both hard drive cages?
Here are some links for reference:
http://www.swiftech.org/Installation_gui...series.pdf
http://www.amazon.com/ORICO-Aluminum-Int...B007VP83BU
https://www.newegg.com/Product/Product.a...6820147568
http://www.newegg.com/Product/Product.as...6822179111
I recommend using SSD for programs and OS, SSHD for data or games (no issues in five years with many drives). Both are available in 2.5" versions.
500 GB SSD
http://www.newegg.com/Product/Product.as...6820147568
1 TB SSHD
http://www.newegg.com/Product/Product.as...6822179111
I’ll post about this on the Swiftech forums.
Loop would be: H220-X2 Prestige → Tee Fitting splitting, sending half the flow to each GFX card
1st T-Branch → bottom GFX Card / 2nd T-Branch → top GFX Card
Returning to GFX cards, use another T-fitting
T-Fitting → 420mm radius
420MM radius → H220-X2 Prestige
Thanks to the substantial thermal mass of the water blocks on the GFX cards, you won’t require much flow. Also, passing water through two cards in series would double the flow rate, almost halving the friction loss through the blocks.
For a similar setup in an Enthoo Primo, see the details below.
I own an XT45-420 on top and a UT60-280 inside an Enthoo Primo enclosure... it's a straightforward build but it's a very large case. The Enthoo Luxe should fit the X45-420 but can only accommodate a 240mm radius on the front as per the manual... so you'd likely need to use the H220 X2 Prestige. Check out the image here for mounting guidance. The instructions suggest following the method shown on the right at the bottom of page 1. I don't have an Enthoo Luxe case nearby, so I can't measure it directly. Not sure if you'd need to remove both hard drive cages.
You still have several options for SSD and 2.5" HD mounts, but if you had to install HDs, you might need one of these to fit a 3.5 HD in a 5.25" bay.
You haven't used an HD in five years... prefer SSD for programs and OS, SSHD for data or games (no issues in five years with many units). You can get both in 2.5" sizes.
500 GB SSD
1 TB SSHD
I'll post about this on the Swiftech forums.
Loop suggestion: H220-X2 Prestige > Tee Fitting splitting, sending half the flow to each GFX card
1st T-Branch => bottom GFX Card / 2nd T-Branch => top GFX Card
From GFX cards back into another T-fitting
T-Fitting => 420mm radius
420MM radius => H220-X2 Prestige
Thanks for the advice. Would you consider a similar setup?
You mentioned:
EK Supremacy CPU Block -
Swiftech Dual DDC MCP35X2 Pump
EK Res 3 Reservoirs
EK Full Cover Waterblocks
plus the two radiators from your Enthoo Primo case.
It seems cheaper to buy waterblocks for the GPU separately and install them individually, rather than combining everything. What are your thoughts? Do you have photos of your setup? You're considering an X99 motherboard. Do you use one reservoir? What is your loop configuration—one or two loops?
If you can't determine the number of loops from his photo, then you should seriously reconsider doing a custom loop...
delta5 :
If you can't determine the number of loops from his photo, then you should seriously reconsider doing a custom loop... I'm not very experienced with watercooling, but I'm pretty sure the picture shows just one loop. Probably not a photo of his computer either. I was wondering how many loops his rig actually has.