H100i RGB Pro XT - i7-7700K (at stock , B250 board) - temps too high?

[marteee]

Seeing temps of ~90 under all core 100% load, doesnt seem to matter which fan profile (Quiet/Balanced/Extreme) I set, the temps settle in at around 90 degrees celcius.  The all core boost of ~4.4Ghz never drops, so it isnt throttling but is it not uncomfortably hot?

Selecting the Balanced profile, the base speed of both fans immediately jumps to about 1800RPM, with the system idle (at around 35 degrees celcius), and again the speeds trickle down VERY, VERY, slowly to a base speed of about 1400RPM (which is still quite loud) but as you can see, this is about 8 minutes of slowing down!....

 

I then set both to Quiet, and it immediately drops, as I wouldve expected the curve to do?:

 

Using this profile the fans seems to max out at about 1050 RPM (both) after running an all core 100% load test for about 15 minutes, averaging 92-93 - but it literally takes about 5 MINUTES to get from 400 to 1050 - why?!.  On stopping the load, instant silence from case fans (220T via a DC curve as theyre 3pin), AIO ramps VERY, VERY slowly back down

The below shows just how slow it is, thats about 5-6 minutes to get up to 1000RPM

 

I think the problem appears to be everything is tied to coolant temp, which makes sense but my main concern is the peformance - why are these temps so high?

Any advice appreciated (and Im hopefully being stupid!)

 

 

[marteee]

Without adding too much rant, the Extreme profile is the same, activating it the fans immediately ramp up to 2400RPM with the system IDLE - here is a screenshot without any load, about 5% utilisation, CPU temp at around 35:

 

Whats also interesting is at this point if I hit the all core 100% load again, the temps are almost identical to the Quiet profile, with only about 5-6 degress difference :

 

 

[marteee]

Edited

 

 

Edited December 3, 2021 by marteee
Im a dumbass

[marteee]

A fixed fan speed of 1100RPM yields the same performance too, around 91-92 within about 30 seconds and stays there

 

[marteee]

Last thing Ive tried is unlatching the speed from coolant temp, which has what I would consider the normal effect on noise:

 

 

Fans immediately ramp when hit with load and drop back to silent when idle, using this curve, temps are actually (weirdly) a tad lower at around 87% at 100% all core

[LeDoyen]

the default fan curves are just bad.. it's not the sensor that is a problem but the presets themselves.

 

You should really just leave it tied to the coolant temp and make your fan curve based off it. When the load stops, the fans should not slow down, they should keep running fast to cool the water down otherwise your AIO will stay warm between loads and it's just wasteful since in average your CPU will keep running hotter than needed.

likewise when starting, there is no need to ramp up the fans since the water is already cool, and the radiators won't dissipate more heat since.. there's no additional heat to dissipate yet.

Always a bit counterintuitive since, the AIO actively cools the water, but only indirectly the CPU

Typicaly people try to keep the water never higher than 45-ish °C, so you could make this your maximum fan speed and use the temp you have at idle as the slowest speed, then make a curve in between. Then tweak from here to taste.

[LeDoyen]

I just looked at the coolant temps you have and 30-32°C at full load is pretty cool.

Seems the AIO is doing its job normally since that's pretty cool water.

The problem seems to be that either the overclock is a bit agressive (high Vcore), or there is bad contact between the CPU and the coldplate of the cooler.

Another thing is the 7700K doesn't have a soldered IHS. there is thermal paste between the processor die and the IHS, and this one is known to dry up and cause poor thermal conductivity. SO if you want to push it hard usually only delidding and repasting it will be able to drop the temperatures massively (not rare to drop 20° or more).

 

Edited December 3, 2021 by LeDoyen

[marteee]

Thanks LeDoyen.  It isn't overclocked at all (board doesn't support overclocking anyway with that chipset I don't think), its all stock.   It is however all on auto, perhaps its being fed too much voltage?  What would a good manual dial-in for voltage be?

 

I tightened everything down again as I did think about the bad mount but its stock thermal interface material as it came (1st install from new) so I would've thought pretty fool proof?

Wouldn't have a clue about delidding it (Ive read a little around it but would never go there!) and no interest in overclocking it, just would like to see it running a little cooler (albeit with an artificial load).  Ran the Unigine Heaven test a few times and gets to around the 80 mark

[marteee]

Isn't it strange though that seemingly no matter what the fans are doing (anywhere from 400 to 2400), the upper temps are basically always the same with the all core 100% load? (90)  - its like the cooler just cannot get the CPU temp lower, regardless of what it does (coolant temps do rise from an idle of about 29 up to low 30s after a long soak)

 

Is that again pointing towards either too much voltage or bad mounting (the latter I just cant see how is possible though)

[marteee]

Thinking more about mounting pressure, would I be able to get the idle temps down into mid 30s if it wasnt mounted properly?  Wouldn't the idle temp but much higher?

[marteee]

"Always a bit counterintuitive since, the AIO actively cools the water, but only indirectly the CPU"

 

That was really useful by the way, should have been obvious but yeah makes total sense!  I guess this also answers why the temperature ramps straight up to the same point regardless of fan state.  Thanks for the tip!

[LeDoyen]

Mounting pressure usually affects the highest temperature reached, not too much the idle temp.

Basically not enough pressure translates to a thicker layer of paste. it's fine at idle, but the resistance is more visible under load where you may lose a few degrees. unless it's REALLY bad mounting, it's usually minor differences.

I don't know how old the AIO is, but repasting the IHS could help recover a few °C. If it's 2 or 3 years old, it may be worth a shot and could get you off the 90s.

 

From what you describe, it really looks like it's just the internal paste that is just drying up. The heat struggles to pass to the IHS, so the cooler keeps the IHS fairly "cool", but the CPU itself is running hot. That would explain why the water doesn't get all that hot.

Edited December 3, 2021 by LeDoyen

[marteee]

Pressure wise I hand tightened in the usual pattern (Top left, bottom right, bottom left, top right loose, then tightening gradually in the same pattern), then tightened off with a screwdriver today to be sure (maybe a quarter turn at the most), I think any more pressure would be excessive from my understanding?

 

AIO is brand new out of the box, so the TIM on the cold plate is fresh, as for the TIM under the IHS - obviously several years old now (and it was a 24/7 machine for the first two years of its life!).

 

Your conclusion is pretty much my own (along with the VCore at AUTO over-feeding it!), but I was hoping to be wrong!

[marteee]

Pressure wise I hand tightened in the usual pattern (Top left, bottom right, bottom left, top right loose, then tightening gradually in the same pattern), then tightened off with a screwdriver today to be sure (maybe a quarter turn at the most), I think any more pressure would be excessive from my understanding?

 

AIO is brand new out of the box, so the TIM on the cold plate is fresh, as for the TIM under the CPU's IHS - obviously several years old now (and it was a 24/7 machine for the first two years of its life!) - so could well be dust!

 

Your conclusion is pretty much my own (along with the VCore at AUTO over-feeding it!), but I was hoping to be wrong!

I'm kindof resigned to it just being "the way it is" - it isnt throttling, maintains the all core boost 100% of the time and as I mentioned the 100% all core load is totally synthetic and not typical of anything my daughter will do with it (Minecraft, Fortnite, Roblox - the usual kid stuff!)

 

Im still all ears for anything else to try though if anyone has any thoughts!

[c-attack]

Your more than 60C+ for coolant to CPU temp differential.  That is definitely either too much auto voltage or bad contact.  Even an overclocked 7700K should have a lower differential.  If it was not doing this before, then I would keep on the mounting investigation.  Maybe one back plate thread isn't all the way in.  Sometimes you can see this with large 10C+ differences between core temps at 100% fixed load.  Bad contact usually results in very erratic temps on the desktop as well.