High Coolant Temperatures

J

jwright33

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Aug 22, 2011
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Had this current custom loop set up for a bit over a year now I think, but only recently was able to get a coolant temperature probe installed. CPU and GPU temps had been what I thought to be good ( 40-50c cpu / 60c gpu ) during gaming, but my coolant temp gets to 52c during gaming. From everything I have seen, that is too high for what I have. I will list out my details to see if anyone can see an issue. Thanks

20c ambient

12900k @ 1.29v 5.1/4.0 all core
3080 EVGA ftw3 +150/600mhz
EK XE 360x60 Front Rad
EK XE 240x60 Top Rad
XSPC Photon D5 170 pump/res ( D5 is vario version, set to highest level )
Both radiators have push/pull Arctic p12 pwm fans ( 10 total ) @ 100% speed
EK black 7/16' id zero maintenance black flex tubing
Generic mechanical spinning flow meter ( spins really fast )
Temp sensor is located in secondary outlet port on the XSPC pump/res combo ( higher temp because of location close to pump? )

Let me know if there is any other information that might help figure this out.

The picture was from when the loop was set up months ago, system was thoroughly bled of air.

The front rad is intake, top rad is exhaust.

The temperature probe location can be seen in the picture as the right most fitting on the base of the reservoir.

unnamed.jpg
 
That sounds right for what your setup looks like. Your front radiator is using hot air to pass through the top radiator. So your temps will be higher than someone who is only cooling with ambient air.
 
Darunion said:
That sounds right for what your setup looks like. Your front radiator is using hot air to pass through the top radiator. So your temps will be higher than someone who is only cooling with ambient air.
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Who cools with only ambient air? Hot air should not be coming off the front rad.

Idk how much it matters, but I'm not a fan of the res being practically pressed up against fans dissipating heat right into it, and then the temp sensor being right there.
 
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Okay hot was the wrong word. But you are pushing that warmer air across your reservoir and using that same air to try to cool the top reservoir. Also i assume you have already checked the fins to make sure everything isnt covered in dust.

Do the temps do anything different with the side panel off the case at full gaming load?

I apologize i dont cool pcs with liquid but i design radiators and cooling systems for led panels in temp controlled environments. Just trying to help with what i can.

And often just conversing in a thread brings more attention to it for getting more help.
 
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Darunion said:
Okay hot was the wrong word. But you are pushing that warmer air across your reservoir and using that same air to try to cool the top reservoir. Also i assume you have already checked the fins to make sure everything isnt covered in dust.

Do the temps do anything different with the side panel off the case at full gaming load?

I apologize i dont cool pcs with liquid but i design radiators and cooling systems for led panels in temp controlled environments. Just trying to help with what i can.

And often just conversing in a thread brings more attention to it for getting more help.
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Oh no worries, Thank you for your input.

This situation is actually with the side door off, so its really best possible situation for the cooling intake.

Radiators are all freshly blown out in last few weeks, but were not that dusty even before cleaning. Only use a dust filter on front intake, dust filter removed from top panel where top radiator exhausts.
 
Do your radiators feel warm at all? They should be quite toasty if your coolant is hitting 50 C. I believe my coolant hits about 40 C (I keep my fans running about 1200 RPM or less) and I can definitely feel the heat coming off of my radiators.
 
Looks like a false reading from your probe. 52c water temp with 20c ambient is like 20c higher than it should be.
Good job with your loop! It looks good 👍
 
The issue is likely a bad temp sensor. If the coolant were hotter than the CPU, that would mean it's actually heating your CPU rather than cooling it. Since the CPU isn't sucking energy out of the coolant and dissipating it into the motherboard, the most likely issue is the temp sensor itself. Swap it out for another sensor (be careful with the leads on the new one) and then you should be good to go.

If you have the budget, another option would be to replace your flow indicator with something like a HighFlow NEXT from Aquacomputer. That offers a much more accurate and consistent temperature measurement in addition to giving you coolant quality and flow rate. One caveat is that it isn't compatible with all coolant types, so that's something you'd want to check out before jumping in.
 
When I ran a setup like yours (depending on if the case side panel was on) made a big (worse) difference. I don't use temperature probes so I can't speak for water temps but judging from the temps of the cpu and GPU and the heat coming off the rads I learned a few things.

Most important rule I learned was to never suck in warmer air from one rad through another rad. It decreases it's efficiency sometimes to the point where it is negligible to even have it.
So the fix is either how you have it with the case open (not ideal warm air still being shot directly into your case and somewhat still sucked up the top rad ) which is better than having no fresh air mixed in with the warm air coming off the first rad first.

This is especially bad if the CPU or GPU are right before the first rad cause the heat hits the front rad before the top rad throwing more hot air into the case where as if it was looped to the top rad first more of the hot air would be ejected from the top roof rad.

During type of setup I learned that the best possible scenario where ALL components would have lower temperature 🌡️ is when you EXHAUST ALL rads none of them intake. This will result in the lowest overall temperatures in case and for your components.
Trust me I tried this many times it is the best scenario for a front and top rad setup. The front is exhausted forward also after you remove the dust filters.
This is better than having both rads Intake. Your temps would be 20 or 30c higher in case if u did that warming the RAM and whatever else up like a furnace in the case. Personally I like having the in case temps as low as possible also.
And you're likely 10c or more higher having the front intake. It's fighting the 2nd rad with hot air when it should be helping identically but it's not it's hurting performance heating up your 2nd rad.
So my suggestion is go exhaust on all rads and see what your results are. In my situation which my old case I had 3 rads and when I exhausted all of them it made a massive difference like 15c.
 
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Why do you guys have hot air coming off your rad? I have a top intake and front exhaust and my case air temp is like maybe a degree or 2 above ambient. Hot air = hot rad = hot coolant = not enough cooling. Then again I run only HWlabs GTR rads with push/pull fans and 2 d5 pumps.
 
NightReaver said:
Why do you guys have hot air coming off your rad? I have a top intake and front exhaust and my case air temp is like maybe a degree or 2 above ambient. Hot air = hot rad = hot coolant = not enough cooling. Then again I run only HWlabs GTR rads with push/pull fans and 2 d5 pumps.
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After a 2 hour session of 600fps comp gaming the heatsoak is maxed out and the rads are blowing warm air. This is normal lol. Why are you running the top as intake and the front as exhaust? My suggestion would be to run them both as exhaust. You will have better performance. I've tried and the results were big.
 
xDiVolatilX said:
After a 2 hour session of 600fps comp gaming the heatsoak is maxed out and the rads are blowing warm air. This is normal lol. Why are you running the top as intake and the front as exhaust? My suggestion would be to run them both as exhaust. You will have better performance. I've tried and the results were big.
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Because I have enough radiator and fans. As said, the air coming off my rads isn't hot, maybe 1-2c higher. I usually run a liquid-air delta of 3-5 degrees.
 
NightReaver said:
Because I have enough radiator and fans.
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That is a given. So do I. My question is why run the air flow in that direction. Blowing the warmer air towards you isn't what a lot of users would feel is ideal. You want the warm rad air moving away from your body. Just curious because I don't see the benefit in having your air flow in that direction.
 
xDiVolatilX said:
That is a given. So do I. My question is why run the air flow in that direction. Blowing the warmer air towards you isn't what a lot of users would feel is ideal. You want the warm rad air moving away from your body. Just curious because I don't see the benefit in having your air flow in that direction.
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The air isn't warm is what I'm getting at.
 
NightReaver said:
The air isn't warm is what I'm getting at.
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Yes it is. Lol. Please bro. It is warmer let's not get picky about wording. It is warmer then ambient for sure even if it's a little bit. It's unpleasant I've tried. Especially with headphones on for hours. I'm talking from experience because I've tried it.
 
xDiVolatilX said:
Yes it is. Lol. Please bro. It is warmer let's not get picky about wording. It is warmer then ambient for sure even if it's a little bit. It's unpleasant I've tried. Especially with headphones on for hours. I'm talking from experience because I've tried it.
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1 or 2c higher is a far cry from the 15 or so you're seeing.

If my rads were ejecting 40+ Celsius air, yeah that'd be an issue.
 
xDiVolatilX said:
No the 15c I was talking about was not what I was talking about when I was talking about your flow direction. You're mixing 2 different points.
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Idk, bring me up to speed. You mentioned case temps 20-30c higher.

My enclosed case temps are 1-2c higher.
 
NightReaver said:
Idk, bring me up to speed. You mentioned case temps 20-30c higher.

My enclosed case temps are 1-2c higher.
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Yeah that's when I was talking about having all rads as Intake. The in case temps would shoot up massively. Felt like an oven inside the case lol.
 
xDiVolatilX said:
Yeah that's when I was talking about having all rads as Intake. The in case temps would shoot up massively. Felt like an oven inside the case lol.
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Oh, I agree. All intake makes no sense. Sorry if that was the point, missed that.

All exhaust would work better, but what do you do about the large negative pressure? I guess if you don't have dust or frequently clean filters, sure.

I try to balance the intake and exhaust.
 
NightReaver said:
Oh, I agree. All intake makes no sense. Sorry if that was the point, missed that.

All exhaust would work better, but what do you do about the large negative pressure? I guess if you don't have dust or frequently clean filters, sure.

I try to balance the intake and exhaust.
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Yeah it is not ideal to run all exhaust if dust is a concern. I did it for a while because I saw much better temps overall that way also because I have a high powered air compressor tank with a high pressure air blower adapter that blows out every spec of dust in my rig in 3 seconds flat 😂

I also tried the one intake and one exhaust and it was still not ideal. The 360 in the front would counteract 360 on tops efforts. Like the intake rad cancelled out the exhaust rads performance.

Which is why I'm asking you. Why do you run the top as intake and the front as exhaust? I feel like your getting the least benefits with this setup?
 
xDiVolatilX said:
I also tried the one intake and one exhaust and it was still not ideal. The 360 in the front would counteract 360 on tops efforts. Like the intake rad cancelled out the exhaust rads performance.

Which is why I'm asking you. Why do you run the top as intake and the front as exhaust? I feel like your getting the least benefits with this setup?
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The former point really doesn't make sense with enough radiator capacity. Warm air shouldn't be going to the 2nd radiator. This sounds like your loop as hot spots which shouldn't exist with enough flow. The temp should be pretty even throughout the entire loop.

Top intake is to help fight dust somewhat. PC is on wood floors and we have cats/ kids. Front intake would suck more stuff in on the floor. As for efficiency, the only thing that can be argued is "hot air rises", but it turns out with forced air ventilation that it's trivial to overcome natural convection in a small area such as a pc case. The heat goes where you tell it to.
 
NightReaver said:
The former point really doesn't make sense with enough radiator capacity. Warm air shouldn't be going to the 2nd radiator. This sounds like your loop as hot spots which shouldn't exist with enough flow. The temp should be pretty even throughout the entire loop.

Top intake is to help fight dust somewhat. PC is on wood floors and we have cats/ kids. Front intake would suck more stuff in on the floor. As for efficiency, the only thing that can be argued is "hot air rises", but it turns out with forced air ventilation that it's trivial to overcome natural convection in a small area such as a pc case. The heat goes where you tell it to.
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I see your points. Question, what is enough radiator capacity for a 13900 or 14900 and a 4090? I have triple rads 960mm of Alphacool copper {two 360s + a 240} with a D5 pump. The temps are very low CPU is 33C idle and GPU is 29C idle. Seem very consistent through all of the rads almost identical further agreeing with you that the temp is pretty even overall. Loop performance get better as the load rises it can tolerate a lot of heat.
Makes sense to run it the way you do if you don't want 🐈 hair in your rig lmao
 
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xDiVolatilX said:
I see your points. Question, what is enough radiator capacity for a 13900 or 14900 and a 4090? I have triple rads 960mm of Alphacool copper {equivalent of two 480 rads } with a D5 pump. The temps seem very consistent through all of the rads almost identical further agreeing with you that the temp is pretty even overall. Makes sense to run it the way you do if you don't want 🐈 hair in your rig lmao
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That I can't answer lol. I run 2x 480mm GTR rads with fans on both sides. Even have plans to add a 3rd slim 480mm in a side slot just because why not. And that's just for a 6800xt and 7900X cpu. Might help that my rads work better the more air you throw at them, hence the dual fan banks. Along with dual d5s.
 
NightReaver said:
That I can't answer lol. I run 2x 480mm GTR rads with fans on both sides. Even have plans to add a 3rd slim 480mm in a side slot just because why not. And that's just for a 6800xt and 7900X cpu. Might help that my rads work better the more air you throw at them, hence the dual fan banks. Along with dual d5s.
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So we are running the same amount of rad. 960mm. Nice. 👍
I didn't wanna deal with 2 pumps. You running same loop dual pump or dual loop?
 
xDiVolatilX said:
Yeah it is not ideal to run all exhaust if dust is a concern. I did it for a while because I saw much better temps overall that way also because I have a high powered air compressor tank with a high pressure air blower adapter that blows out every spec of dust in my rig in 3 seconds flat 😂

I also tried the one intake and one exhaust and it was still not ideal. The 360 in the front would counteract 360 on tops efforts. Like the intake rad cancelled out the exhaust rads performance.

Which is why I'm asking you. Why do you run the top as intake and the front as exhaust? I feel like your getting the least benefits with this setup?
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That shouldn't happen as long as your loop order is correct. You might lose about 50% (this penalty decreases as the coolant-air delta increases) of one radiator's performance, but certainly not 100%. The exhaust radiator should always receive the hottest coolant while the intake radiator should always be after the exhaust radiator in the coolant flow path.

Running an old Azza Genesis 9000 with a top 480 and bottom 280, maybe it's time for an update. My first case was the original CoolerMaster Cosmos which I cut up to accept a top 420 and bottom 360.
 
Tsumi said:
hottest coolant
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Properly flowing loops really don't have this. You don't have hotter coolant here and cooler coolant there. It equalizes out across the entire loop very quickly. You're talking maybe, MAYBE, a difference of like 1-2 degrees.

Found this out when I first started and was like "I'm going to check the liquid temp between the inlet and outlet of the radiator to see how much it drops" The results were...well...nothing.

I think people get hung up on applying laws of physics that exist, but only matter on larger scales. Much like "hot air rises so put exhaust at the top", it just doesn't really apply or matter at the scale of a PC case.
 
NightReaver said:
Properly flowing loops really don't have this. You don't have hotter coolant here and cooler coolant there. It equalizes out across the entire loop very quickly. You're talking maybe, MAYBE, a difference of like 1-2 degrees.
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This is only true for small builds.

The underlying math is pretty simple:
(mass flow) * (Specific Heat of coolant) * (temp change of coolant) = Heat Dissipated
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Working from flow rate in Lph and assuming specific heat of the coolant is the same as water and the coolant density is 1:
(Lph/3600) * (4184) * (Temp change in C) = Heat dissipated in watts
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If flow rate is 1gpm (227Lph)....
(227/3600) * (4184) * (1) = 264w
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...then we see that at a flow rate of 1gpm, our loops dissipate (or absorb) 264W per 1C change in coolant temp. Note that this is fixed regardless of radiator size. If you run a traditional routing of CPU into GPU into radiator, then the coolant coming out of the hot section will be 1C hotter than the coolant entering the hot section for every 264W TDP whether you're running a single 120mm rad or quad 560s.

If you're only seeing "maybe, MAYBE" a 1C temp delta in your coolant, then that simply means you have a low TDP build (and/or your sensors need calibration). On the other hand, if you're playing games on a build with a 4090 and a CPU that won't bottleneck it, a 3C delta is much more realistic.
 
Thunderdolt said:
This is only true for small builds.

The underlying math is pretty simple:


Working from flow rate in Lph and assuming specific heat of the coolant is the same as water and the coolant density is 1:


If flow rate is 1gpm (227Lph)....

...then we see that at a flow rate of 1gpm, our loops dissipate (or absorb) 264W per 1C change in coolant temp. Note that this is fixed regardless of radiator size. If you run a traditional routing of CPU into GPU into radiator, then the coolant coming out of the hot section will be 1C hotter than the coolant entering the hot section for every 264W TDP whether you're running a single 120mm rad or quad 560s.

If you're only seeing "maybe, MAYBE" a 1C temp delta in your coolant, then that simply means you have a low TDP build (and/or your sensors need calibration). On the other hand, if you're playing games on a build with a 4090 and a CPU that won't bottleneck it, a 3C delta is much more realistic.
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I said 1-2. 3 is like...still nothing. Sorry guys, with enough pump and cooling capacity loop order doesn't matter.

Chasing every % of radiator efficiency just doesn't matter unless you're doing a really passive system.
 
NightReaver said:
I said 1-2. 3 is like...still nothing. Sorry guys, with enough pump and cooling capacity loop order doesn't matter.

Chasing every % of radiator efficiency just doesn't matter unless you're doing a really passive system.
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kind of interesting with 840MM of radiator in my loop I see a 6 degree delta before and after the rads... That is a far cry from 1-2 degrees difference. Single D5 Pump turned all the way up, 1 5950x with Heatkiller IV, 1 7900xtx Liquid Devil, and 2 Alpha cool rads in loop. Cooled by 6 Noctua Industrial 3000rpm Fans
1699123640842.png
 
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NightReaver said:
I said 1-2. 3 is like...still nothing. Sorry guys, with enough pump and cooling capacity loop order doesn't matter.
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You said that 1-2C would be an extreme top end of what could happen. The reality is that 3x your extreme top end is actually the right number for a fairly moderate build. It's ok to be wrong. You don't have to dig your heels in to prove yourself.

with enough pump and cooling capacity loop order doesn't matter.
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With enough pump and cooling capacity, I'd run a radiator the size of a USB port while Chuck Norris tears dripped out of the exhaust. Sadly, I live in a world where there are limits to pump, radiator, and fan capacity.

As for your repeated assertion that the air inside of the case is barely warmer than ambient, it turns out that we can use the same equation to figure out how much hotter the air should be after passing through the radiator. By my calcs using the numbers from Secnario 1 in q-zone's fan test, with a 360mm rad that has beQuiet Silentwings 3 fans spinning at absolute max RPM, that's 1.62C per 100W load. Step down to a maxed out ML120 Pro (1600rpm version) and the number becomes 2.16C per 100W. With a 500W 4090, the Corsair setup leads to a 10.8C increase in air temp. Running the fans at a more realistic 60% speed, the temp rise for the 500W load becomes 19.3C. That is a huge jump. Even with dual 360s cutting it down to 10C, that's still a big jump.

Those calcs are assuming 100% radiator efficiency, so the real numbers are going to be around 20% higher than that. This is why it is important to get as much fresh air into radiators as possible, and it's why the second radiator in a series generally performs poorly when it is fed air that has been pre-heated by the first radiator.
 
Just going to agree to disagree. I'm not even saying you're wrong. But actual experience shows it matters much less. When I started custom watercooling around 15 years ago I thought the same way.
 
Enigma said:
kind of interesting with 840MM of radiator in my loop I see a 6 degree delta before and after the rads... That is a far cry from 1-2 degrees difference. Single D5 Pump turned all the way up, 1 5950x with Heatkiller IV, 1 7900xtx Liquid Devil, and 2 Alpha cool rads in loop. Cooled by 6 Noctua Industrial 3000rpm Fans View attachment 610968
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Maybe the type of rad matters? I specifically went for ones that scale extremely well with the more air you push at them. Then I sandwiched them inbetween fans. GTR 480s. Scale with air flow like no other pc rad.

*Edit* Blah, naturally my aquasuite doesn't want to load up. Yet another thing to fix.

*Edit 2* Geez, It's been so long since I've done work on my pc that I forgot apparently at some point I did put the front rad as intake and top exhaust, and that the top is some barrow 360mm. Front is the GTR 480. I do have another GTR for the top and a side slot, but just never got around to moving it around. Poor neglected PC lol.

*Edit 3* Well I wanted to do some temp testing. Stress tested the 7900X and 6800XT for half an hour, but turns out it's a bit hard to determine anything with just a kitchen probe. Need to get aquasuite back up so I can get my liquid temp reading back. One thing I don't like is yeah, the res being infront of the front rad is absorbing a decent bit of wattage and "pre warming" the coolant. The air itself coming off the rad is about 3c higher, but the water inside is going to absorb it. The top rad is puilling in air that is between 2-4c over ambient, but that's a shaky measurement because, well, kitchen probe and lots of air streams + the gpu backplate is giving off quite a bit of heat as well. This is after passing through the front radiator. I should get a cheap temp gun to check rad temps, sometimes tells me holding a probe to the side won't do much good.
 
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NightReaver said:
Maybe the type of rad matters? I specifically went for ones that scale extremely well with the more air you push at them. Then I sandwiched them inbetween fans. GTR 480s. Scale with air flow like no other pc rad.

*Edit* Blah, naturally my aquasuite doesn't want to load up. Yet another thing to fix.
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Well if you are running 840MM of cooling area and I am running 840MM of cooling area, with half the fans, and I am seeing a 6 degree difference in temps before and after the rads and your are showing only 1-2 degrees difference on the extreme side of things would that not make your loop less efficient at removing heat?

My sensors do not account for the heat added by the pump (as I do not monitor coolant temps before they reach the first rad directly only when the temp goes into the res so added heat from the pump is not in the equation)

The reason that I say this is, I am running Alphacool Nexxos st30 rads, Very thin compared to a GTR 480.

For comparison your 6800xt pumps alot less heat than a 7900xtx at full tilt (Undervolted, +15 PW Limit, Core set to 3100 and Memory @ 2600). Not sure about your 7900x and the 5950x. (5950X is running CO, Undervolted and overclocked)

That Being said you are pumping less heat and seeing a lower delta on both sides of the rad, I am pumping more heat and still seeing a higher delta in coolant temps on both sides of the rads so that would make it seem that my loop with lower fin area (due to rad thickness, They have the same FPI count) and less fan capacity (only without knowing the spec for your fans) makes my loop more efficient.

My Rads draw air from inside the case (fed by 4 Noctua 2000rpm Industrial 140MM fans), The ambient case air temps are 32C at idle, case fans try to keep ambient are temp at 32C and ramp to full at anything above that.

The only 2 variables that we have that are likely different are my ambient temp (27C) and my fan speed (I allow mine to run full tilt as needed, my Aquasuite is set to keep coolant at 33C anything above that and fans run at full speed)

Noise in my case is alot higher I am sure. :)

#edit : Currently running prime95 16 threads small fft, with kombustor for 1/2 hr will post results when done.
 
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Ah my fans are the Corsair ml120s. Not going to do as much work as the noctuas, that's for sure. The only separate case fan is a single 140mm at the back.

The before and after rad temps don't matter. It's all about how cool your coolant is above ambient. Now I know why my aquasuite isn't running, I don't even have it installed in this case yet, nor the sensors.

In my previous 900D I ran a curve on aqua suite to keep the air-liquid delta at around 3c. My loop was working better in there (also took more care) due to more space, more fans, etc. The current 7000D doesn't provide nearly as much space. My res was also clear out of the way of rad output. It was a cd bay mounted one.

So yeah, I'm sure my current loop is less efficient due to inferior setup and just plain disregard.
 
NightReaver said:
Ah my fans are the Corsair ml120s. Not going to do as much work as the noctuas, that's for sure. The only separate case fan is a single 140mm at the back.

The before and after rad temps don't matter. It's all about how cool your coolant is above ambient. Now I know why my aquasuite isn't running, I don't even have it installed in this case yet, nor the sensors.

In my previous 900D I ran a curve on aqua suite to keep the air-liquid delta at around 3c. My loop was working better in there (also took more care) due to more space, more fans, etc. The current 7000D doesn't provide nearly as much space. My res was also clear out of the way of rad output. It was a cd bay mounted one.

So yeah, I'm sure my current loop is less efficient due to inferior setup and just plain disregard.
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#30 Min Loop Complete

2C Delta from Rad outlet to ambient (Slightly Less)

7C or Almost Delta from Res inlet to Rad outlet

Loop order = Pump -> Rad -> Rad -> CPU -> GPU -> Res/Pump

View attachment 611003
 

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Yeah now I'm curious and wish I had my previous loop/ case to do a real test.

Kids taking all my time away to work on this stuff lol.
 
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