H110i GT & i7 6800K high idle temps

My i7 6800K is slightly overclocked to 3.8GHz and on idle it's 38C with ambient temperature of 23C. Load temperatures are perfectly fine - 51C. Pump is working on 2800RPM and fans are at 1300RPM.

If the load temps are as expected and it is only the idle temperatures out of frame, then you are likely looking for a BIOS or Windows Power Plan setting and not a cooler issue.

 

1) Make sure you are not set to the High Performance Windows Power Plan. This will keep your processor in 100% minimum state almost all the time.

 

2) If you set certain combinations of fixed/manual voltage and disable C-States/EIST in the BIOS, you will see higher idle temperatures corresponding the elevated CPU activity. Most people do no need to disable these features and there is a very real heat and energy cost to keeping the cores up and running a constantly.

 

What motherboard are you using for this pairing? What does your H110i GT Temp read when at idle (coolant temperature)?

I just redid the tests here are the results:

Idle CPU temp with all fans running on maximum RPM is 36C and the coolant temp at idle is 32C. That is with ambient temperature of 22C.

Also I don't know why, but CPU package temp is rather higher than all individual cores. All cores are at 28-30C while the CPU package is at 36C.

I have High Performance power plan enabled in windows so all cores are running at 3.8GHz at idle.

Load CPU temp (10 minutes of AIDA64 stress test) is 48C and the coolant temperature on load is 36C.

CPU package still is 5-6 degrees higher than all individual cores.

Motherboard I use is Asus ROG Strix X99 Gaming

BIOS settings are all at default so I haven't touched anything except enable XMP.

Somehow I lost a "not" in reference to high power plan. If you wish to run with all cores full active, that's up to you. It will of course give you a higher idle temperature.

 

XMP can change other things besides the memory timings, including the multiplier and strap. That could change your frequency, but I think it is unlikely in this case. The board should stick with the 38x100 multiplier when DRAM is set to 2666MHz. Still, take a look the next time you go into the BIOS.

 

Ignore package temperature. It is a little quirky on HW-E and BW-E. Mine is sitting at 36C right now, despite my warmest core at 24C. At idle, it always sits +10C over the CPU (average) temp, but then drops below CPU temp when loaded.

 

The difference between the room temperature and the coolant temperature is a little surprising. An actual CPU idle temp of +4 over coolant is normal and if you look at the individual cores I suspect they will bounce around the 32C. All is good there. However, that +10C coolant delta over room temp is where you are losing ground. It really should be just a few degrees above the room temperature, depending on power level settings and C-states.

 

Where is the H110 GT located? (I assume top) Which way do the fans move air? (Intake or exhaust?) Are there any other environmental factors that might restrict the airflow or prevent heat from escaping the case area? (dust filter over radiator, case wedged into a corner, under a desk, etc)

 

How does the coolant (H110 GT Temp) compare the motherboard temp reading from any monitoring program?

My case is NZXT H440 so it has dust filters on the front fans. The radiator is on top as exhaust and the fans are pulling air from the radiator. The PC is in open area, its not in some corner or under desk. One strange thing i noticed is that my motherboard's VRM temperature is 54C at idle. On load it's 60C. Is this normal?

The front fan filter is fine. One on top of the radiator would be too limiting for most people.

 

OK, H440 then. I suspect that may be the contributing factor. It has the solid top with vented sides like a lot of low noise cases. Normally, I prefer to exhaust the waste heat out, but that may not be as functional with that top design. You'll need to keep that rear fan up to speed when gaming, since it has to remove all the CPU and GPU waste heat. At some point, you could try flipping the fans around to exhaust. I am not sure it will make a huge difference, but everyone should always experiment a little.

 

As for now, compare the motherboard temp sensor to the coolant temperature at idle. That may give some indication of 'warm case' or restricted air intake for the radiator. Also, the next time you cold boot or wake from sleep, take a note of both temperatures and then watch them over the next 20 minutes while doing normal desktop stuff (not gaming or stress tests). Do they rise at the same rate? Does the coolant temp go up and the motherboard temp hold steady?

 

Obviously your load temperatures are quite good and idle temperatures have little effect on longevity, but I assume you would like to be as efficient as possible.

As for the VRM, I do think that is a bit warm but I also suspect you are still on the default AUTO settings in BIOS for power management. That is something you want to change on X99's.

 

Go into the BIOS. Hit F7 for the Advanced BIOS, then right arrow over to AI (Extreme) Tweaker.

 

Go down until you see External DIGI+ Power Control. Hit enter.

 

This will bring up the sub-menu pictured here. That is for a Sabertooth, but it doesn't matter other than color.

 

Go to CPU VRM Switching Frequency and change it from AUTO to OPTIMIZED. You don't need the VRM in full phase switch at your levels or even mine at 4.5GHz. That should take some degrees of the load and idle. You could also change CPU Load Line Calibration to something in the 5-6-7 range, however at 3.8, I think you are fine on Auto. If you decide to overclock further, 6 or 7 might be a good choice. The AUTO is a little to slow to ramp up when needed and then stays at max level 9 for too long.

 

The above should help some, but part of the issue is dumping your CPU waste heat onto the VRM heatsink at the top of the board (that little piece right above the socket). If you blow 32C air on it, it will start off at 32C plus the voltage induced heat from normal operation. Your VRM temps are still in the safe zone (under 70C), but I think this is one of the key values to watch on X99 and I pay more attention to it than CPU temperatures. In fact, I run my fan speeds from that number.

Thank you very much for your help. Im currently using the default rear fan for my case which is only 900RPM. Is getting a better rear fan going to help to reduce the coolant and VRM temperatures?

You could get a fan that goes a little faster at the back, but 1000 rpm on a 140 mm is about all you can get. There are some slightly higher speed fans, but I would consider this a minor tweak rather than a stand alone solution.

 

I think we've narrowed down the cause of your high idle temps. Knowing where the come from should take some of the worry away. At this point, you need to decide whether you prefer to run with the top as exhaust or with the top as intake and endure the higher total case temperatures. I know what my preference would be, but you are the one who will be sitting next to it. Whichever you choose, I don't see any serious consequences at this point.

What would be your choice?

Each instance should be treated as unique and there are no universal rules. However if I have the option to dump waste heat out the case, I usually take it. There are some specific uses where it may not matter, like pure number crunching machines, but a mixed use PC that sees combination High GPU/Moderate CPU loads (gaming) will put a lot of heat in the case. If you have an open, non-blower style GPU you can really warm things up. It's not that internal components will fail, but if you had the option to reduce every single component in your case by 10C, wouldn't you take it?

 

All that said, sometimes unique case elements, location, or furniture make that not an ideal set-up. I think you should turn the top fans around to exhaust and find out. However, before you do that, make sure you get a general motherboard temp sensor reading for idle and gaming for your current set-up. Save a LINK snapshot, HWMonitor, whatever. I suspect CPU temps will be more or less the same. However, I am hoping the idle will come down a little and the internal case temps while gaming will come down a lot. Then you can make a proper decision.

Well currently my top fans are exhaust. They always were exhaust. My top fans are pulling air from the radiator, but they are on top of the radiator. I wanted to place them below the radiator, but the case doesn't support that, the radiator is too long to be on top and I had to place them on top of the radiator.

The radiator is on top as exhaust and the fans are pulling air from the radiator.

 

OK, this threw me off and I saw intake. If you are currently using them as exhaust, take note of the same variables and try them as intake (label side down). For temperature purposes, push or pull won't matter but can certainly affect the sound they make. This does make the high idle coolant temperature a little more puzzling.