H100i GTX water temperature questions

Hi,

 

I've had a H100i GTX for quite a while now and I've got to admit I've never really gotten to grips with it.

 

I always had a problem with the noise level associated with the water temperature. The three standard profiles all run the fans at 100% as soon as the water temperature hits 40 degrees and the noise is just too much for me. I first swapped the fans out for SP120 QEs and I now have ML120s, which are better but still loud at 100%.

 

What I would like to know is what a safe temperature for the water is, to help me set a custom curve? Should 40 degrees be the upper limit? If so I have a problem in that my 4690K, while not getting much above 50 degrees under load, does push the water temperature above 40 degrees. For example, after a few hours of Zombie Army Trilogy today with the fans at 70% - which still isn't quiet - the water temperature was at 45 degrees. Is this safe?

 

It would really help me if someone could share the custom curve they use to keep both the noise level and the temperature sensible, because I really don't know what I should be doing. The H100i GTX is my first water cooler, I've previously used air coolers and I've got to say they seemed better at keeping the noise down. I fully expect to be told I'm doing something catastrophically wrong, but I'm happy to admit I'm an idiot if it helps me learn!

 

The system is installed in a tower case with two 140mm intake fans on the front panel, a 140mm exhaust fan at the rear, and the H100i GTX at the top of the case with the fans blowing through the radiator to exhaust out the top.

 

Any and all help is welcome!

 

Thanks.

So ... I think the core of your issue is that your GPU's waste heat is flowing through the radiator. As a result, the radiator isn't cooling as much as it should.

There are a couple of ways to handle this. The easiest is to flip the fans to intake. Second, manage the case fans in the front based on a temperature other than the CPU - the CPU isn't really a relevant control temp for the case fans anyway as its not dumping its heat into the case. Ideally, you'd base the case fan speeds on the internal case temperature, not the CPU temperature but if you have the case fans controlled by the motherboard, your options will be somewhat limited. Some motherboards do accept a temp sensor that can be used for this. Otherwise, another option is the Commander Pro, which has 4 temp sensors that can be used to control fan speeds.

Over the years this has come up frequently in relation to the BeQuiet series cases. People with fairly normal hardware, not pushing overly hard, and yet continued elevated coolant temperatures. Looking at the product page for the 801, it looks like it follows a common "noise suppression" tactic of sealing the top, then allowing some venting in a small rear portion. While there is a pathway, this creates a fair amount of restriction which in combination with a radiator proves to be too much. In effect, the heat gets trapped in the noise suppression layer and transmits heat back to the radiator. Unfortunately, that is kind of how these things works. It retains one type of energy, it retains them all.

 

I don't have an immediate suggestion beyond what was said above. Flipping the fans may not work because the pathway is still restricted, but it also might be better in not retaining the heat layer above the radiator. It would going to the case for rear exhaust. The other option would be moving the radiator to the front, but without having the case and trying I can't tell you if it is a better.

 

Your coolant temperature is your baseline CPU temperature. If the coolant is 40C, then the CPU is 40C at 0 volts. Of course, you are never at zero volts when powered on and the actual CPU temp with be additive to the coolant temp by some offset directly related to the voltage level. I would be very surprised if your CPU temps only get into the 50s with a 40-45C coolant temp. Even at stock clocks, you should be a 20-25C offset and resulting temps in the 60-70C range. There is nothing inherently harmful about 40-45C liquid temps for the cooler, but that is the point where some CPUs start to get near their limits, especially overclocked or newer ones that run hot out of the box. Since a high coolant temp is a universal penalty with no positive tradeoff, you would prefer it to be lower. The fans can be managed and at this point I would go to a fixed speed system for you while playing. Set the fans manually to highest level you can stand, - 100 to 200 rpm. It's a slow and steady kind of thing. You don't need them to be reactive. You can then set them to a comfortable desktop level when finished. The other option is to bump up the standard curves to do the same thing in the temperature range you are in. However, at this point some more pointed attention may be required to learn exactly what that range is and a little bit of manual control may help develop an understanding of what's going on in there.

Thanks for the replies, I will try reversing the fans. As for the case fans, they're plugged in to a manual fan controller and I always set them to maximum before gaming. I can't hear them over the H100i fans as soon as they ramp up anyway.

 

Is there a maximum safe coolant temperature that I must not exceed? This will help me figure out if it's possible to make the cooler work quietly enough.

 

Before I had the Silent Base (a failed attempt to block horrendous coil whine from the Vega 64) I had the same parts in a Cooler Master Cosmos S, which was meshed on the front, side and top, and the H100i would still go over 40 degrees in any game.

 

As a final question, is this just what the H100i does? What I mean by that is, by and large, would you expect the cooler to go over 40 degrees when gaming with a 4690K? If so, I feel I would probably be better off replacing it with something designed to be quieter?

Corsair does not specifically list a temperature limit for their AIO coolers. Generally, other manufacturers publish a number between 50-60C. However, this is largely based on the inevitable end CPU temp in the 90s at that level. The rubber hoses and plastic are rated above the boiling point, so not really a concern from a material standpoint.

 

Another way to assess any effect the top panel has on cooling is to remove it and see if temps drops. In particular, I am wondering if drop at idle and what you idle coolant temps are normally like (in comparison to a room temperature). It is possible the AIO has an issue all in its own, but I also do not expect a 4790K or most any other CPU to heat the coolant above 40C. At stock voltage, you might see a +6C rise, so unless you are starting in the mid 30s at idle, something else is going on.

 

In the meantime, you have control of the fans. The 40C=100% fan speed line is based on two things. 1) You have a normal baseline room temperature of 20-23C where a +17C rise in coolant temp over ambient represents a massive change. 2) That you may have a moderate overclock where CPU temp differential to coolant is +40-50C and thus a 40C coolant temp puts you at 80-90C. That is certainly an area where you can't slip any further and need maximum fan speed.

Room temperature is currently 20.6 degrees, PC has been on for about seven hours but only for office work, coolant temperature is currently 34.8 degrees and the CPU core temperatures are bouncing around the mid 30s.

 

I'm not overclocking and the cores are clocking up and down as you'd expect, rather than running at full speed all the time.

 

I take it my temperatures should be.a lot lower than this?

Most people will see an idle coolant temperature of +4-7C above their room temp. This is definitely case and location dependent (a front intake is always going to be slightly better than top exhaust). However, at +14C or so it does suggest something else is going on. I would pop the top off now at idle and see what happens. If there is an airflow restriction or heat trap, the coolant should start to slowly tick down almost immediately.

I feel like I'm getting somewhere now, thanks!

 

I took the side panel off and slid the cooler out from under the top panel to expose the radiator (less screws than taking the top panel off!). After 30 minutes the coolant temperature dropped to 30.6 degrees and is holding around there. Room temperature has gone up to 21.8 degrees.

 

This is on the quiet profile with the fans still set up as exhaust.

 

Is it conclusive that I need a different case or is it worth switching the fans to intake?

If you slid the top tray out and the radiator is essentially in room air, it really should have a coolant temp down somewhere in the mid 20s at the most. Your CPU is only throwing off 25W or so at idle and even if it is spiking up here and there, that does not really contribute to the total watts that need to be dissipated. While I am using a different everything than you, my coolant is sitting at 24C for the CPU+VRM block out in 21C room, in a case with no active intake fans. My H115i AIO is no different, although it sits at +2C over ambient all the time in a highly ventilated case.

 

I think the thing to do is run a quick test of the AIO itself. While it is still hanging out on the fan tray, load up a mild stress test like Intel XTU or the "Bench Stress test" in CPU-Z. That last one is linear and mild, so CPU temp should be steady most of the way through. Run it for 10 minutes with the fans fixed at 1300 rpm. Expected coolant rise for a 4790K stock is +4-6C for those tests with that fan speed. If you come out at +10C in free air, we know the cooler has an issue.

I've run the CPU-Z bench for ten minutes and the coolant temperature has only gone up to 33.1 degrees. The CPU cores are between 46 and 50 degrees.

 

What next?

I've just run it for another ten minutes with the case closed up and coolant is at 36.20 and still climbing and CPU temperatures are between 52 and 57 degrees.

The coolant delta (+6C) is reasonable and does not indicate a failing unit. The coolant-CPU differential (+15-20C) is good, so no contact problem, although that really wasn't a concern. What remains is a really high coolant temp compared to your room temp. I doubt I ever made it to 36C in the life of my H115i Pro, even in Summer when the room temp is 27-28C on a hot night.

 

I don't know what to tell you. I don't really want to say "go get a new case", but it certainly appears it is environmental. I suppose the smart intermediate step is flip the radiator fans to intake. You will still be warmer than expected, but hopefully that will keep the GPU heat out of the equation. 36C is certainly better than 45C.

Edited March 30, 2020 by c-attack

Another ten minutes with the case closed and the fans set to intake and the coolant temperature is at 32 degrees with the CPU temperatures at 46-52 degrees.

 

I'm going to be honest and say I'm surprised it made that much difference!

 

Thanks for your help!

4C is a good improvement. There are no miracles when it comes to radiator performance. Environment is always the big stick. Now the real test will be if it hold up under your normal mixed use (GPU + CPU) vs the artificial test conditions we created.

Good news: The coolant temperature didn't hit 40 using the quiet or balanced profiles over an evening's gaming for basically the first time ever.

 

Bad news: One of the ML120 Pros has started rattling. Annoying but easily replaced.

 

Thanks again!