Watercooling - max recommended water temp and fan question

[boxleitnerb]

Hi guys,

only recently have I begun to control my fans by my water temperature. The idle water temps seem a bit high though. I reach 34-36°C (95° F) with fans turned off.

My system:

• 4790K@4.5@1.15V
• GTX 970@1400 core
• Mora 3 9x140mm external rad (akin to the Phobya Xtreme Nova 1080, only larger) with 9x Noiseblocker Black Silent Pro PK-1 (140mm)

I know passive cooling has its limitations, but how much heat are CPU and GPU going to dissipate in idle? GPU maybe 10-15W, CPU the same. That is basically nothing for such a potent cooling setup. Is that normal?

Then my second question concerns the fans on my rad.
The PK-1 are fine fans, but some of them exhibit a slight rattling from the bearing that is annoying me. I exchanged 2-3 of them some years ago, but I honestly believe this is normal and this model just has a wide variance in regard to bearing noise. Is there any good alternative for a push configuration?
I'm thinking Silverstone Air Penetrator or Noiseblocker eLoop (once...IF...they ever are released as 140mm fans). Or something else?

Thanks!

 

[Essence_of_War]

I think the general rule of thumb is ~10C above the ambient temperature, but usually people test that with the radiators actually operating properly

How does your water temp look with your fans actually running under loads?

 

[BonzaiDuck]

I think the general rule of thumb is ~10C above the ambient temperature, but usually people test that with the radiators actually operating properly

How does your water temp look with your fans actually running under loads?

That's really the big question. I've got my eye on the MO RA3 and other external radiator solutions, but I'm planning to use internal radiators when I "step up" to water this year.

Look, for instance, at my latest project -- pretty much identical with the sig except that it uses an SB 2700K and a more compact, more effective heatpipe-tower. With a 4790K @ 4.4 and 88W of thermal power, what would the temperatures be like compared to my SB @ 4.7 and ~140W?

My IntelBurnTest load temperature average-of-maximums is around 71C with room-ambient ~77F. Another user overclocked his 4790K to 4.6 with temperatures around 70C, an AiO (H80) cooler with special attention to pressurization and airflow. He insisted that his thermal wattage was STILL 88W. He also concluded the extra 200Mhz didn't amount to a hilla-beans in performance. And at 4.4Ghz, his load temperatures are in the high 50's C.

My idle package temperature is about 33C -- maybe 14F above ambient. That won't matter for anything. Figure the processors are more or less intended to operate comfortably below 73C at stock load. I'm pretty sure my idle temperatures are a result of my fan-SPEED choices; I'd be a lot closer to room ambient allowing them to spin up faster at the lower temperature range.

Another project-in-progress on this forum involves a 5820K and MO-RA3, modestly overclocked and showing the same temperatures around 70C.

I agree with the thoughts about the Noctua iPPC price, but you're going to pay above $15 each for any decent fan -- am I wrong? That would be a lot of iPPCs and a lot of money for the MO RA3. I'd say if the OP is going to "go that route" with 9x fans, the less-expensive lower-RPM models should serve. Personally, I"d try to do it with 4x 180mm fans or a similar configuration.

 

[Squeetard]

My rule of thumb. I don't care really how high temps get under load as long as they don't slowly increase over time until they get too hot. You want enough rad/fan so that it can keep a stable temp under load.
My vid/cpu temps never top 60c, I think that is plenty good. Idle is 35c too. Really aren't going to get better than that either as those are on die readings.

 

[Essence_of_War]

Guys, be careful, OP is asking about their water temperature not their CPU/GPU temp!

The idle water temps seem a bit high though. I reach 34-36°C (95° F) with fans turned off.

 

[boxleitnerb]

Just found out that Samsung SSD Magician made a custom power plan, never allowing the CPU to go into idle clocks (800 MHz). Saved 15W right there, temps are better now. I can run Prime FFT and Furmark (or something of the sort) and check the water temp.

I've been running Prime95 small FFTs and Furmark for about 10 minutes now. Fans are running at 4.5V, so about 400 RPM give or take, water temp is currently at 31.6°C. It seems the Mora 3 is very bad for passive cooling. Sufficient for idle, but under load it would crumble very very quickly.

 

[aigomorla]

most rads are bad for passive running...

You would need like a radiating tower to get acceptable passive performance.
And even then, the closer you got to ambient the harder it would be for the passive system to keep the coolant there.

Generally the smaller the FPI (fins per inch) on the rad, the better it will do with less air movement, but it will cost a bit of performance compared to a very high FPI radiator.

Higher FPI rads require powerful static fans to push air though the restriction.

Also your gpu uses way more then 15W even in idle, unless ur not running a full cover block.
The heat generated from VREGS, and Ram, also add up.
Rule of thumb i say is take full wattage of said gpu when in idle and take roughly 70-80% of that number as heat.

the only way u will get lower is if ur entire gpu was made of a super conductor or a near super conductor like material, where nothing is lost and everything is preserved.

so example..

76W * .8 = 60.2W of heat...

that should be approx heat your gpu is dishing out in idle.

I think the general rule of thumb is ~10C above the ambient temperature, but usually people test that with the radiators actually operating properly

How does your water temp look with your fans actually running under loads?

thats seems about right in the approx...

(values represent full stress figure... take (water temp - ambient temp = ΔT))

ΔT =
10-15C -> considered borderline for custom watercooling.
7C-10C -> Mid Tier LC
4C - 7C -> High Tier LC
1C - 3C -> you have too much money to burn, and i dub thee watercooling elite!

1-3C systems cost well into the 4 figure area.... as they require large large radiator surfaces and high performance expensive fans.
Well there are expections like ur runnning a Low Voltage CPU on a CPU only loop on a MORA or Phobya... But lets ignore those...

 

[BonzaiDuck]

ΔT =
10-15C -> considered borderline for custom watercooling.
7C-10C -> Mid Tier LC
4C - 7C -> High Tier LC
1C - 3C -> you have too much money to burn, and i dub thee watercooling elite!

1-3C systems cost well into the 4 figure area.... as they require large large radiator surfaces and high performance expensive fans.
Well there are expections like ur runnning a Low Voltage CPU on a CPU only loop on a MORA or Phobya... But lets ignore those...

Generally my GTX 780 settles around 35C at idle with the stock two-fan cooling. Gaming it peaks to around 70C @ 100% usage. If we're talking about idle temperatures and room-ambient is something like 25C, then I can grasp the meaning of these figures. To me, the fundamental question is delta between the idle temperature and the load temperature.

I'm taking all this in. Learnin' new stuff every day . . .

 

[boxleitnerb]

GPU 60W at idle? No way - my entire system draws 58W at idle now. GPUs idle at 8W to 25W ranging from GTX 750 Ti to GTX690.
http://ht4u.net/reviews/2014/palit_geforce_gtx_970_jetstream_im_test/index15.php

Those 58W include losses at the power supply, SSD, motherboard, soundcard, pump, fan controller (aquaero LT), RAM, CPU and of course GPU.

 

[BonzaiDuck]

GPU 60W at idle? No way - my entire system draws 58W at idle now. GPUs idle at 8W to 25W ranging from GTX 750 Ti to GTX690.
http://ht4u.net/reviews/2014/palit_geforce_gtx_970_jetstream_im_test/index15.php

Those 58W include losses at the power supply, SSD, motherboard, soundcard, pump, fan controller (aquaero LT), RAM, CPU and of course GPU.

If you're responding to AigoMorla, I don't think he said that. I think he meant there was other thermal wattage coming from the graphics card VRM and other components. Just a minute while I hit the KVM . . . I'm not all sharp-in-the-head about this topic, but I watch the HWMonitor reports, and I can measure my PSU draw through the UPS/battery software.

For a processor that shows 140W Package power for OC'd IBT load, the entire system at idle is using no more than 85W, and as I recall, the processor uses mostly ~ 16W as a central value of a range -- lowest of 13W. One hard disk; two SSDs; 16 2x8GB RAM. There's nothing else connected. The gfx card is an old GTX 570. I'm contemplating a double purchase, and I'm going to take my time.

 

[aigomorla]

GPU 60W at idle? No way - my entire system draws 58W at idle now. GPUs idle at 8W to 25W ranging from GTX 750 Ti to GTX690.
http://ht4u.net/reviews/2014/palit_geforce_gtx_970_jetstream_im_test/index15.php

Those 58W include losses at the power supply, SSD, motherboard, soundcard, pump, fan controller (aquaero LT), RAM, CPU and of course GPU.

you do know messuring the power though the PCI-E 6 pin is not accurate.
Power is also distributed via PCI-E lane itself on the motherboard.

The 6 pin provides extra power outside the ones which the PCI-E slot draws.


Well you can take any figure you like... honestly...
but i have a hard time believing a videocard can draw less wattage then the pump your most likely using to move water in your watercooling loop.

a DDC uses 18W, and a D5 ~ 20-25W...

 

[boxleitnerb]

you do know messuring the power though the PCI-E 6 pin is not accurate.
Power is also distributed via PCI-E lane itself on the motherboard.

The 6 pin provides extra power outside the ones which the PCI-E slot draws.


Well you can take any figure you like... honestly...
but i have a hard time believing a videocard can draw less wattage then the pump your most likely using to move water in your watercooling loop.

a DDC uses 18W, and a D5 ~ 20-25W...

My 58W are measured at the wall. My pump uses about 6W, the video card should use around 15 or so.
Most sites that measure power consumption of the video card itself reach similar values (HT4U, hardware.fr, TPU, PCGH...). I just meant to say that the dissipated head of my system during idle conditions is very small compared to the cooling capacity of the radiator. Thus my amazement how bad it fared running in passive mode.

P.S.
I'm using a full waterblock of course, cooling VRMs and VRAM.

 

[aigomorla]

what pump are you using that is only drawing 6W?

it cant be a DDC or a D5... i already told you the values for those pumps..

 

[james1701]

What about the premise that long term water temp above 35C promotes plasticizer issues?