Cooling issues with AIO Water Coolers

[Schui1024]

Hi all.

Bit stumped on this one, hence the post.

Case is a BQ Dark Base Pro 900.
CPU is i7 2600k (4.5ghz)
GPU is 780ti (no overclock, I know, I'm waiting for the next gen nvidia series to upgrade the rig)
I'm running 5760x1080.

I have 2 x 140mm intake fans on the front
1 x 140mm intake fan at the bottom.

There's 1 x 140mm output fan on the top, and 2 x 120mm fans on the GPU AIO Cooler (120 rad, push pull), and 2 x 120mm fans on the CPU AIO Cooler (also 120 rad, push pull)

I'm running all the fans from the case fan controller, which by default is on the low setting.

At idle, the CPU temp is average at around 35-40, and the GPU is the same, around 34-36.

When gaming, the CPU tops out around 58-62 odd, which has always been the case.
The GPU however gets higher than I thought it would. I'm using a Corsair H75 with Kraken G12.
It will around 66-68 in game, and I've run gpu benchmarking and get the same results.
With the fans on full it's down to around 54-56, but the fan noise in not fun.

Reviews and videos of the G12 on GPU's show them running around 45 on full load, so I'm unsure why mine is so hot. The top of the case is incredibly hot, (The Dark Base Pro 900 has some limited air vents at the top so I've dremelled out all the plastic bits in the way to help airflow)
I've also tried removing the top completely and the temps are still the same.

I've also applied thermal grizly and checked the AIO is fitting correctly.

Airflow in these BQ cases isn't the best, but with the side panel and top off it only drops the temps by 3-4 degrees.

Anyone got any ideas as to what to try next? Or any experience water cooling the 780ti? The case is under a desk but with good ventilation, only the heat coming out the top is cooking my knees!

 

[ameyer75]

The reason you're getting more heat on the GPU than the CPU is this: GPUs are just warmer. They're built to run at higher temps. There's also the silicon lotto that you have to keep in mind. If you were telling me that you were running at 80C under half load, we'd have to investigate the issue.

That being said, 68C is a pretty GOOD temp for your GPU to be running under 100% load. I wouldn't bother worrying about it.

 

[vMax]

Agreed with ameyer75 just in case you need validation...those are good temps all around..

 

[1LiquidPC]

Temps are fine and look normal. The temp difference you may be looking at could be from cooler on a lower TDP card. For example, on PC Gamer the temp dropped from 80C to 45C on a GTX 1080. The Founder's 1080 is a 180W card, whereas the 780 Ti is a 250W. This could explain temp differences.

 

[Schui1024]

Many thanks for all your responses. Getting the same temps with the side off so realise it won't get much lower than it is.
Will hold out for the 1080ti's to drop then prob upgrade the lot.
Got a 240 aio going spare so may drop that in and see if that helps in the meantime.

 

[1LiquidPC]

A 240mm radiator would drop temps, as it's doubling cooling capacity for the GPU. GPUs use considerably more power(high end anyways) than CPUs and the extra heat needs dissipated.

 

[bmockeg]

As others have stated, your temps are fine. Theres no need to have the side or top off. If your temps aren't hitting 90+ you are completely fine.

 

[rubix_1011]

Here is your clue:

Airflow in these BQ cases isn't the best, but with the side panel and top off it only drops the temps by 3-4 degrees.

Indicating that your case airflow is poor. Best case scenario is that your temps would be the same or slightly cooler with the case side panel on, since this would allow the case fans to tunnel air correctly through the case and out.

Also, like others have said, you're also trying to liquid cool a 250w TDP card with a 120mm liquid cooler that isn't really built to handle this load. Good 120mm radiators (built from brass and copper) typically top out at 150-160w for a 10C delta-T unless you are running 2000+ RPM fans in push+pull. This would be your best, budget-friendly solution here as well.

Those AIO radiators are not the best thermal conductors since they are manufactured from aluminum. Thermal conductivity of metals is just one of the issues at play here (https://en.wikipedia.org/wiki/List_of_thermal_conductivities)

The other being the menial flow rate provided by the pump. I've actually measured the flow rate on Corsair AIO's and it's something like 0.9 liters per minute. (http://www.tomshardware.com/forum/id-2834038/corsair-h110i-gtx-performance-testing-review.html

At this point, I modified the setup for my test bench. I connected the pump unit to my custom built reservoir and my King 7530 3.5 GPM (gallons per minute) flow meter to see what kind of flow performance the pump actually had. This has been one of the long-standing debates around these coolers – what the actual flow rate of the coolant is, and due to voiding of the warranty, not many people have actually wanted to find out.

The flow for this cooler is very low and didn’t even register against the float in my flow meter, which tells me the pump also operates at very low pressure. Given that this cooler is never meant to operate in a capacity more than the pump and radiator alone, this isn’t at all surprising to me. I removed the unit from the flow meter setup and decided to go with an old-fashioned flow rate test, falling back to a digital stopwatch and a 1 liter beaker. I timed five separate, one-minute intervals to ensure I was getting consistent readings.

What I found was somewhat (but not completely) surprising. The pump consistently produced a flow rate result of 0.25 GPM (gallons per minute) or 0.95 LPM (liters per minute). For comparison, most of us in the watercooling community try to shoot for a flow rate goal of 1.0 GPM (3.785 LPM) in their custom loops. Another curious fact I noticed was the drop in flow rate when I raised the tubing end from being on-level to the pump to 18 inches above; flow rates dropped by almost 0.25 LPM – down to around 0.70 LPM (0.185 GPM).

 

[ameyer75]

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