Water Cooled: GPUs and CPU slowly heating

b1177a · Feb 27, 2016

I have been trying to sort out this problem for a few months now, with little improvement. Hopefully someone might be able to shed some light on some paths I can take to remedy the problem.

I had installed my first water cooling loop around this time last year. It consisted of the following:
Res -> Pump -> Rad -> CPU (i7-4970k) -> GPU (GeForce 780Ti) -> Res ->

I had great temps at the time. At load my GPU was around 45-50C, and CPU around 60C.

I got a hold of a second 780Ti and decided to SLI it into my system. I didn't include it in the loop, but it ran without any issues on air only.

I subsequently decided to add it to the loop, so I bought a second radiator and a new PSU and hooked it all up. As follows:

Res -> Pump -> Rad1 (Ex240 (top)) -> CPU -> GPU1 (water bridge) GPU2 -> Rad2 (RX240 (bottom)) -> Res

I subsequently started to get worse performance and a LOT of heat in my case during load.
Idle : GPU and CPUs all mid 30Cs
Load: GPUs - 65-70C, CPU 75-80C

It didn't shoot up all at once, it would start off with great temps but after about 15 minutes they would slowly build up. The inside of the case would be too hot to touch, and the water temps would be hanging somewhere around 45-50C.

I decided that I had poor ventilation, so I changed my initial fan setup (All pull except for a single exhaust on push) to all push. That didn't work very well, so I changed it to the setup you can see in the attached image (Bottom rad pull, top rad push, front pull, rear exhaust). That helped a bit, but it really just slowed down how long it took to heat up. So I decided to buy some more powerful fans. Again, some improvement, but just slowed down the time it took to heat.

I tried pulling the GPUs and CPUs apart and applying more thermal paste and reseating, no change.

All the tubing is going into the correct ports.

I have currently ordered 2 high static pressure Noctua industrual fans for the bottom radiator, and will put the fans currently on it onto the top radiator (which has poor static pressure). However I am not confident that this will fix the problem. I've also tried adjusting the fan speeds, and even at all of the fans at 100% it still heats up.

As such, I was hoping there might be something I missed? With water temps hitting the 50C mark I am worried that I will damage my components.

My setup can be found here:

http://imgur.com/jM9SDNX

My Specs:
CPU - i7-4790K (RayStorm CPU Waterblock)
GPU - i) EVGA Geforce 780Ti with EK Full waterblock
ii) Geforce 780Ti with EK half waterblock
Motherboard: MSI Z97 Gaming 5
RAM: Kingston DDR3 8gb x2, Kingston DDR3 4gb x2 (24Gb total)
SSD: Samsung 850 EVO
PSU: Cougar 1050W GX1050
Case: Corsair C70

Water cooling - D5 Dual Bay Resevoir, D5 Vario Pump
XSPC Ex240 Dual Radiator with (Fans: XPSC 1650rpm 120mm (x2))
- Mounted top (push)
XSPC RX240 Dual Fan Radiator V3 Black with (Fans: Corsair SP120 x2)
- Mounted bottom (pull)

Additional Fans:
Noctua 120mm NF-S12B Redux Edition 1200RPM Fan (rear exhaust - push)
Corsair SP120 x2 (Front of case) - Pull
Corsair SP120 x1 (post HDD) - Pull

Thanks

Mr Kagouris · Feb 27, 2016

First of all let's get out of the way that push or pull does not affect temps. This has been tested and proven. The only difference is how your rig looks. My guess is that the bottom fans have trouble pushing enough air through that thick rad. I'd say wait for the Noctua fans and report the results.

1LiquidPC · Feb 27, 2016

Not enough radiator(480mm total)would be my guess. 588W tdp of parts to cool between your CPU and GPUs with no OCing. What RPM are your radiator fans spinning? Also, is your water cloudy, or is it just showing up like that in your pic?

Mr Kagouris · Feb 27, 2016

He has enough rads (that huge 240 in the bottom would be enough to cool the CPU and one GPU on its own), but, as I said, this kind of heat soak is consistent with inadequate dissipation. So when you have enough dissipation area, naturally the only other thing that you could lack would be airflow, so in all likelihood the bottom fans can't push enough air through the huge rad, but I'm betting those Noctua industrial fans will. We'll just have to wait I guess.

b1177a · Feb 27, 2016

Thanks for the input, I will try out the Noctuas and see how they go. The water is clear, its just the photo that is making them look off.

rubix_1011 · Feb 28, 2016

Push and pull does make a difference - I've tested this. However, it depends on the fans used and the radiator they are used on. It also depends on the thermal load the system is cooling. Even around 300watts of load, you can see up to 1.5-2C difference in delta.

toolmaker_03 · Feb 29, 2016

sound like the largest issue here, is a low flow rate issue with the water loop system.
what pump is being used for this system?
I would also consider adding 4 more fans to the radiators, it cant hurt the system to try it right?
other than that, I do have a thread that shows how low flow rate can affect the performance of a system.
http://www.tomshardware.com/answers/id-2767231/serial-loop-parallel-loop.html

b1177a · Mar 1, 2016

The Noctua fans arrived today. I installed them in addition to lifting my PC off the ground a bit more for hopefully a bit better airflow underneath. They have definitely made a difference, just not as large as I would have liked.

With FurMark running at full capacity, 99% usage on both GPUs:

Pre Noctua:
@ 15 minutes:
GPU1: 65-68C
GPU2: 63-65C
With Noctua:
@ 25 minutes
GPU1: 59-61C
GPU2: 57-59C

So there has been some change, although not as great as I would have hoped. It is taking longer for it to heat up and staying at a decent temp for longer, but seeing similar setups I feel like I should be getting much better temps. A friend has the same SLI setup, except they have a closed loop CPU cooler and the cards are both air cooled, and it is overclocked, and their temps are still better than mine.

@ toolmaker_03 - I am using an XSPC D5 Dual Bay Reservoir/Pump Combo

I have thus far been taking my water temps with a turkey thermometer, and will be getting a proper temp probe in soon so can comment on water temps once that happens

1LiquidPC · Mar 1, 2016

Looking to see what your water temps are with the new probe. On idle this time of year, mine settles at around 26C after an hour or so. My internal case air temp with another probe stays 2-6C cooler depending on load. I believe the highest I've noticed during several hours of summer gaming is about 35C.

b1177a · Mar 2, 2016

Temp probe arrived.

Ambient temp - 28C
Idle temp - 29-30C (CPU and GPUs)

After playing Dying light on ultra settings for 90 minutes:
CPU - 74C
GPU1 - 61C
GPU2 - 58C
Water temp (reservoir) - 49.9C

The Noctua fans definitely helped with the GPU temps but the CPU still seems to be going nuts, and a water temp of 49.9C makes me very nervous.

My top res fans have an SP of 1.8, so I guess I could try getting something a bit more powerful there, but otherwise I'm at a loss for now.

My pump speed is set to 2 (of 5) but increasing it doesn't seem to make any difference

Thanks everyone for your thoughts so far. Any more ideas?

1LiquidPC · Mar 2, 2016

What are your rad rpms? Are your radiators high or low FPI? Possible you have a restriction somewhere in your loop. I had a single 480mm top mounted radiator in my 800D for cooling before. I was cooling a 375W TDP Radeon 6990 and i7 3930k 130W TDP before OCing. I had 4 38mm fans in pull on my radiator. My CPU temps stayed under 60 normal load or barely over 70 in prime95. My 6990 never went over 54C on each GPU core in gaming. I was using MCP655-B pump, which always runs at 4500 rpm. My temps were fine to me, but my setup was loud. I ran radiator fans around 2500rpm or so if I remember.

Possible for you to rig up your loop to run along with temp probe and fans without the rest of your system on? Curious to see what temp water goes to with no load.

Mr Kagouris · Mar 2, 2016

Considering the CPU has a much lower TDP than the GPUs then the CPU temp issue sounds like a problem with CPU-waterblock contact. Try re-applying some good thermal paste.

4Ryan6 · Mar 2, 2016

My first thoughts is to agree with 1LiquidPC, you do not have enough radiator cooling field to get the job done.

That said regarding what you do presently have in operation.

The best way I see from your picture to improve your cooling is use both the rads as exhaust, turn your rear exhaust 120mm fan around as an intake, maybe even get higher CFM fans as rear and front intakes and supply all the fresh air into the case you can supply for the radiators to exhaust out.

In your situation you need more air coming into the case than is being exhausted which will be a slight positive pressure advantage.

Your picture shows the bottom radiator adding it's heat to the case, that's why after a time period the temperatures rise as it gets hotter from the loop load, so your top radiator is getting preheated air.

More than one GPU seriously changes things which now you are learning the hard way.

Mr Kagouris · Mar 2, 2016

I really doubt that he doesn't have enough dissipation area since he only needs to dissipate about 600W with CPU and both GPUs maxed, or that the heated air is affecting things in any meaningful way. He's got two front intakes pulling in way more cool air than his radiator is pushing in hot air, and even if the heated air affected temps it would steadily do so, not cause heat soak.

4Ryan6 · Mar 2, 2016

Mr Kagouris :

I disagree!
That's why I posted what I did!

Mr Kagouris · Mar 2, 2016

But how would a normal 240 + a thick 240 rad not be enough for only a CPU and two mildly hot GPUs? And how would heated air cause heat soak when it's being exhausted?

toolmaker_03 · Mar 2, 2016

because in reality, two normal 360mm radiators are just barley enough for a CPU and two GPU's. it works better with three 360mm radiators but two will work.

http://www.tomshardware.com/answers/id-2767231/serial-loop-parallel-loop.html

1LiquidPC · Mar 2, 2016

Glad to see I'm not alone in thinking the OP may not have enough radiators. I often see the use 120mm of radiator per device being cooled, but I don't really agree with this "set in stone" logic. An 88W vs. a 130W CPU for example. Also, a 250W TDP per GPU are not "mild" cards regarding heat/voltage for keeping temps in check. I'm thinking it either not enough radiator capacity and heat isn't being dissipated well also causing the high temps including water itself, or a restriction somewhere. Again, with my old setup I mentioned a few posts ago, I had to deal w/ a lot of noise from my fans for being WC'd to get the temps I had. My 480mm radiator was a HW Labs Black Ice GTX480 54mm model.

rubix_1011 · Mar 2, 2016

I'm not sure where '120mm per component is a good rule of thumb' ever originated, but it's not a very accurate or very good estimate since there are so many variables that go into determining loop delta. Plus, what size 120mm...how thick? What flow rate? What fans? What FPI? I think that many people see a closed loop cooler that is a single 120mm and assume that is the size needed to cool any heat producing component, but in reality, it's typically not enough for a CPU, especially when overclocked. And I am in complete agreement with others here - running 600w of thermal load (before overclocking) is a lot to put onto dual 240 rads, even thick profile ones. The cooling delta is almost certainly suffering due to the radiators not being able to dissipate enough thermal volume to keep up with the load.

b1177a · Mar 3, 2016

Thanks for all the advise.

So keeping everything in mind, what would be the best way to troubleshoot this?

If the radiators are the issue, what would be the best option? I imagine trying to find another option to replace the top radiator, but then what would work best? The motherboard will prevent a thicker rad at the top. Perhaps a radiator that was a bit longer? If so, any suggestions? Ideally I don't want to have to mount anything outside of my case.

Alternatively, if it is a flow restriction issue I imagine I should get a flow sensor, although they are not cheap either.

As I said before, I reseated the CPU already, but I will give it another shot.

I feel like I am nickle and diming myself to death with this. All part of the process I suppose.

Thanks again

1LiquidPC · Mar 3, 2016

To be honest, I'd consider a bigger, more WC friendly case and an additional radiator. If you turning your pump to 5 from 2 setting doesn't change things, and plenty of water turbulence in your reservoir, I doubt restriction is the cause. I know this is the most expensive option to consider, but you're trying to cool a lot of heat generating parts, even if you don't OC. Under a GPU load especially, your generating a lot of heat. I was using San Ace 38mm thick 120mm fans 9G1212H1011 if I recall, or a similar model # on my 480mm radiator setup. I had 2 140mm NoiseBlocker PK-3 intake and 1 140mm exhaust fans(same model) besides the radiator fans. My setup was likely lower TDP to cool than yours even with my CPU OC'd. Plenty of folks on here that have custom loops will be either CPU only, or CPU and GPU. For your setup though, you're cooling 2 higher end GPUs along w/ your CPU. That's a pretty large demand for cooling. This is why I'm thinking it's going to take more cooling capacity to bring your temps down while keeping fans at a lower speed/lower noise setting.

b1177a · Mar 4, 2016

For the time being I think I will let it sit - I feel like another radiator would probably fix the issue, and I don't really want to drop $40 on a flow sensor just yet.

Via Afterburner I have set an FPS limit and a Temp Limit of 60C. That has at least allowed me to keep a water temp of 38-40C.

Perhaps in a few months I will invest in an external radiator and see if that fixes things. Any suggestions on external radiators? I was looking at this one:

http://www.au.aquatuning.com/water-cooling/kits-und-systems/external-kits/15644/aquacomputer-aquaduct-360-eco-mark-ii-externe-wasserkuehlung-mikroprozessorgesteuerte-12-v-pumpe

But would that be enough (if i linked between my 2nd radiator and my res) and would I likely require a more powerful pump if I did?

4Ryan6 · Mar 4, 2016

b1177a :

You may not have the extra money at this time, but you do have the time, to do what I suggested to you.

The best way I see from your picture to improve your cooling is use both the rads as exhaust, turn your rear exhaust 120mm fan around as an intake, maybe even get higher CFM fans as rear and front intakes and supply all the fresh air into the case you can supply for the radiators to exhaust out.

In your situation you need more air coming into the case than is being exhausted which will be a slight positive pressure advantage.

Your picture shows the bottom radiator adding it's heat to the case, that's why after a time period the temperatures rise as it gets hotter from the loop load, so your top radiator is getting preheated air.

Not trying to offend you but according to your picture your setup is pitiful, your top front intake is blocked by your HDD cage and the bottom front intake is partially blocked by the lower radiator, the lower radiator is intaking air into the case which heats as the system heats which is canceling out the fresh air from the lower front intake.

There you have the case temperature slowly building from the heat!

Your rear exhaust cannot produce magical air to pull out with your present setup.

Turn the rear exhaust around as an intake, will not only supply fresh air into the case, it will help cool your motherboard voltage regulators that you removed the cooling from, you do realize the stock air cooler you removed was actually not just cooling the CPU but the voltage regulators around the socket.

Without the needed air to cool them they also produce extra heat, and will eventually fail, they have to be cooled!

If not the longevity of your motherboard will be compromised.

The way your picture setup looks, right now you don't have case air flow, you have case heat flow!

Take a good logical look at your picture and fix it!

Good Luck! Ryan

b1177a · Nov 10, 2016

Alright, so it has been awhile since I asked this question, but it has all come to a head. The real answer is I was a dumbass, but I'll paint a story and TL;DR it at the end.

I followed the advice of this thread and made a wide array of changes, including more fans, different fan directions, raising the PC off the floor (all of those made very minimal difference), clearing away some of the obstructions, removing radiators, rearranging radiators, different coolant, pump speed modifications, etc. I managed to get a good balance but still not quite as good as I was hoping, but it would do temporarily. I ended up getting that Aquaduct 360XT Mark V external radiator. Took out my old big thick radiator and put it neatly in a drawer somewhere.

After setting all that up the temps were substantially better, I was getting consistent temps of around:

CPU 68C
GPU 1: 52C
GPU 2: 53C

Was looking good, and the passive cooling away from the rig seemed to be working great. Plus the fan controller was fantastic to have. Still though, the water was hotter than I would like it to be, but c'est la vie, right? During a test run of Dying Light (my go to testing game) my temps were nice and I was getting pretty consistent rates of 144fps (most of you will probably see where I am going with this now...at the time however, I did not).

That night I went to shut off my monitor, and my finger slipped, hitting the Hz button on the monitor. A nice white "60Hz" popped up in the middle of the screen, and the penny dropped. Obviously in my initial question I failed to mention that I have an ROG ASUS Swift G-Sync monitor, with swappable Hz of 60, 120, and 144. It was set firmly on 144Hz. Prior to building my new rig I had JUST bought the monitor, and wasn't really doing any heavy lifting with graphics, so didn't notice anything. When I finished building my rig I obviously wanted to try to max out the graphics on a game. I didn't make the connection to the monitor (obviously).

So, lo and behold, if I change it to 60Hz or even 120Hz my temps are ice old or luke warm respectively. The additional changes I made were a great learning experience, so thanks to everyone for chipping in on that. Plus now I guess I can run at 144Hz and still get respectable temps. The biggest joy for me is that I have an answer to my problem and I'm not insane (just dumb)

So there you go. Hopefully this conclusion helps someone else down the line!

TL;DR: Monitor was running at 144Hz, the cooling I had in place wasn't enough to handle that. Changed it to 60Hz (and 120Hz) and temps much better. Also followed the advise in this thread and optimized my air flow, so all good now.

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