H115i Pro RGB temps high

Hi. I am new with water cooling. I changed i MB and my CPU to GB Z390 Aorus Ultra and i7 8700K OC to 4,8 GHz. I installed a new H115i Pro for the cooling but i think that my temps are quite high and unstable. To idle HWMonitor detects CPU Cores at around 37-40C degrees mainly with Package to be even more 5-10C. My temps are not stable i believe changing all the times between 37-50C and when i use any game my temps goes 80-85C. With Prime95 100-105C.

I have spikes even to 73C.

I set up fans and pump through iCUE to balanced mode but even at extreme it does not change a lot the things.

Checking the dashboard of iCUE i see the pump rpm not to be linear but having repetative spikes. Is this normal?

I reseat the cooler, tight the screws more, untight the screws but temps are not changing a lot.

Any help will be appreciated.

Thanks

Temp spikes in modern CPUs are absolutely, positively normal. Temps of 100C aren't expected. However, the cooler may not be the reason. What voltage are you running when you run Prime95 (this would be vCore or, in iCUE, vCPU).

 

Also, you need to include your coolant temps, especially when you hit 100C.

Hi again and thanks for the reply. I am not sure that i understand the question but in Bios i set up the cpu voltage to 1,285V. Coolant temp is 38,5C. According Prime95 vCores 1,223. I run the test again and now my avg temps are Core 0 at 95, 1 at 91C, 2 98C,3 95C, 4 97C, 5 92C. All of those after about 40 mins running Prime95.

Coolant temp is idle on the desktop at 38C? Or after that long load? Either way, coolant temp differential is the key, so you need a starting and ending point for the measurement. You really shouldn't more than a +6-7C change on a 280mm with a 8700K. Most people have idle coolant temps 4-6C above their room temperature or at a minimum equal to the case internal ambient temperature.

The 38C are after the load. I start with 29C about.It should be ok since in the room i have 23-24C. The thing i think how much do i expect to raise with full load.Because if the 38,5C are not hot enough when i run Prime95 means maybe that i have not a good contact between cooler and cpu right? So first when i have the cooler working to extreme using Prime95 what should i expect as a water temp? Edited October 4, 2019 by Baltazar77

If the coolant is raising that high, you do have good contact ... it means that the heat is being transferred.

The question is why it gets that warm after load. Are the fans exhausting from the case or intake from outside?

I have an NZXT S340 case. The radiator for that case you can put it only at the front in push mode and intakes air. The 2 case fans back and top are exhausting. I have a GTX 1070 too in case it matters! I was thinking to try change the original thermal paste. What do you believe? Is it worth the time? Because i read that most of the people they didn’ t see big difference.

Thermal paste would make the heat transfer more efficient. Since that's really not an issue (your coolant is rising quite nicely), that would have minimal impact.

As your airflow is intake, it rules out issues from GPU heat (mostly, at least).

What does your fan curve look like?

And what happens if you remove the front panel on that case?

Checking the dashboard of iCUE i see the pump rpm not to be linear but having repetative spikes. Is this normal?

 

Yes, but if you look closely the actual RPM isn't changing by much and it is always in units of 30 rpm. The program is using a rounding calculation to the turn the 2 second polling interval into a per minute number we expect, but I have always suspected on the Pro coolers it rounds before the multiplication, and thus you get +-30 rpm. However, this then amplified by the way iCUE treats its graphs. This is literally turning a molehill into a mountain. Whenever you have a really tight range, it narrows the graph range to match and any change looks enormous. Conversely, if you range was all over the place, the changes would look tiny. Visual graph error. We have all been hoping for a slightly different treatment of min/max and the graphing range, but it doesn't look like that is on the present agenda.

 

The coolant temps seem right, but the idle CPU temps do seem a little high. Make sure you compare this with the Vcore at that moment in time and your Windows power plan. Lake processors rarely sit still and even background programs are enough to keep clocks and voltage up. In turn, aggressive BIOS settings in regards to power saving might also do this (like turning them all off). See if you can get a reading with minimal other activity and watch the Vcore to see if it is riding in the 1.2x range.

Thanks both for the help. I will check as soon as i will be back home because i am out now. What i was thinking is that maybe it is quite hot the case inside. Before the installation of the new Mb cpu and the h115i with that case at the front i had no fans. I had only the 2 exhaust fans back and up 120mm both and my temps with an OC i5 6700K to 4.9 and an average fan cooler were ok. Now which I installed in the front the big fans of the h115i and intakes the room air through the hot radiator, I suppose that the air which comes into the case it is kind of warm correct? Are those two exhausts enough to take out this air? What if i change the exhaust fans with better ones in terms of cfm?At the top i can put a 140mm in back no. Do you believe that can make a difference? Both of the exhaust fans now are connected to the PSU so they work 100% all the time.

Well, changing them to higher speed fans won't necessarily solve the problem and you'll get into a higher negative pressure scenario. What we've seen help several folks is to flip the top fans to intake (rather than exhaust).

Hi again. I tried some things. First changing the upper fan from exhaust to intake changed nothing so i left it as an exhaust. I read somewhere that i have to run Prime95 without AVX enabled. Disabling this gave me 4-5C less. Taking out the front panel temps decreased 3-4C more. So finally i managed to have to the cores from 77-84C and 85C at the package. At the end i brought down to 1.250 the vCore but did not change anything. I see the system stable till now so i will leave it there. Last thing i noticed that the water temp came down to 32,5C.

How do you see this?

I will suggest not using Prime 95 as a temperature diagnostic tool. That's not what it's for. If you have a cooler problem, all things will result in unusually high temperatures. Prime 95 will result in high temperatures whether you system is in tip-top shape or not.

 

If you need to try a quick and consistent test when you think you might have an issue, try the stress test from CPU-Z under the Bench tab. It is linear and light. Your cooler should be able to handle it easily. It should immediately jump +30-45C depending on voltage and then hold steady. Any further temp increases are from coolant temp rise and you should be able to match that with the H115i Pro Temp in iCUE.