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H100i Pro Coolant Temp 30C i7-8700k Temp 75-90C


TheDiagGuy
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Hello,

 

I know I'm inquiring about a WELL covered topic on this forum, so let me start by saying I've spent several hours pouring over the search function on this issue.

 

The issue:

My i7-8700k with H100i Pro gets CPU temps from 70-90C using the "userbenchmark" engine while the water temp NEVER rises. EVER. over 30C

 

At idle the CPU temps are around 40-50C

Under 100% load they spike to 75-90C with a minor overclock

With no overclock they rise to about 60-65C under full load.

As soon as the CPU load is gone the temps quickly drop to about 50C for the rest of the benchmarks.

My cooler is mounted in the Exhaust position in the top of the case and I have two intake fans and one other exhaust fan.

I have a turbine fan GPU so it pushes heat out of the case rather than spraying it everywhere inside the case. (Yes I know turbine GPU's run a little hotter because of this)

 

What I've tried based on the search function:

Reapplied thermal paste with Corsair's own fancy brew.

Verified water block is actually tight on CPU socket.

Set CPU fan to 100% in BIOS

Set iCue fan and pump settings to extreme.

Fan RPM at all times - ~1000

Pump RPM at all times - ~2700

Can hear water/air moving upon first startup of system after sitting overnight.

The hoses both do not get hot at all.

 

Since the temps come down after the CPU test it leads me to believe that the AIO is working to some degree, but it sure can't cool very well...

 

Also: I have a H100i v2 in my other rig with a 4690k and a minor overclock and have nearly identical issues. In this rig the AIO is mounted as an intake because my GPU is an open shroud design. Temps are 40-50C at idle and rise to 75C under load then back down to ~50C off load and water temps NEVER rise over 28C. Did all the same steps as above with this rig as well. I used to have a dual fan tower heatsink on this rig and it cooled the CPU much better than this AIO currently is.

 

What am I doing wrong? Could both of these AIO's have faulty pumps or restrictions?

 

Thank in advance!

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There is a difference between "my coolant never goes above 30C" and "my coolant is always 30C". Typical expected coolant rise from CPU heat only for an 8700K is +5-8C with a 240mm cooler. You would need a max load of at least 5-10 min to see that. Short 60 second benchmarks will never create enough long term heat to overwhelm the system.

 

This is in contrast to "my coolant is always 30C". If the coolant never moves during load (gaming or stress tests), that is indicative of contact problem. The heat is no being transferred into the coolant stream effectively. However, usually in this state the PC is difficult to use. Opening a browser or folder creates a massive stress test-like temp spike.

 

With all current CPUs, voltage and CPU temp is the limiting factor. The cooler does not make your CPU cooler. It prevents it from being even hotter. That seems like a meaningless distinction, but it is a result of the physical nature of the relationship. Heat originates with the voltage at the socket pins and must travel through the CPU to get to the cold plate and cooler - air or water. The water is simply a transport method for the heat, not a cold shower.

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Thank you for your replies and for putting up with my obvious ignorance. This is my first time tackling water cooling. Thanks for breaking it down for me so I can understand better. I appreciate that. The Coolant temp does go above 30C when under constant load with no overclock - Got as high as 35C which supports your statement about the coolant temp increase. Haven't tried it yet with an overclock. I believe I may have some misguided expectations for water cooling. I always thought it would run cooler so you could support higher clock speeds (and vCore now that you point it out) but it seems to me from what I've learned so far that the point of water cooling is essentially to be able to maintain higher clock speeds not necessarily achieve higher clock speeds since the media for heat transfer is larger on a water cooler than most tower heatsinks. Am I understanding correctly?

 

Here are the vCore numbers you requested. This is at 4.7 GHz and 5 GHz.

The 90C temps only hit at 5 GHz.

292316170_LoadvCore5_0GHz.thumb.png.1c4261d6f0489833c1b4f24de72bd242.png

1030012635_IdlevCore5_0GHz.thumb.png.39f8062ebc71e5735f3f1cbbc86f2420.png

771384898_LoadvCore4_7GHz.thumb.png.cbd044190c0589909ec5342d83100962.png

1209818982_IdlevCore4_7GHz.thumb.png.0b38f9e50bc1e23842c8b667772c09a3.png

Edited by TheDiagGuy
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OK, well the good news is you do have something you can do to lower temps. You likely used "Auto" Vcore for your settings and if you look at the 5.0 GHz setting, the voltage touched 1.40v at one point and is at 1.32 for the snap shot. That's a lot. My 8700K is delidded and I certainly can't take 1.40v wtih 3x360mm radiators (nor should you). I'll put 1.35v as the max you should be working with for daily use and you can likely do 5.0 for less. Most 8700/8086 owners can run 5.0 GHz at 1.25-1.30v. Compare this to the stock peak temps at 1.248v max and you can see the clear temp differences. This is just voltage ruining your day.

 

Try the following in the Advanced BIOS:

 

SVID Behavior: Best case scenario

Set core behavior to 'sync all cores' not per core (for now)

Multiplier 50

 

Half-way down the AI/Extreme Tweaker Column: DIGI + VRM (sub-menu)

Load Line Calibration at the top: change it from Auto to 4 or 5. Of the top of my head, I think the Prime has 6 LLC levels. However, no matter if it is 7,6,5,4 whatever, you want 1-2 rungs down from the top. If 6 is max, set 4. If 4 is max, set 3.

ESC back to main menu.

 

Further toward the bottom:

Change the Vcore setting from "auto" to Adaptive. This will create another drop down box underneath the line you are on. Where it says "additional turbo mode voltage" enter 1.30v. Leave the offset alone. This will keep you on adaptive voltage (like auto) and drop the vcore at low clock levels. Anytime the clocks go above 4.4, then the 1.30v kicks in.

 

See how this goes. The Vcore typcially needs minor tweaking up or down, but 1.30v is a conservative level for most people. It should bring immediate temp improvements vs the auto setting that was using 0.10 to 0.14v more volts.Temps slide up really fast above 1.35v.

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Thank you for your replies and for putting up with my obvious ignorance. This is my first time tackling water cooling. Thanks for breaking it down for me so I can understand better. I appreciate that. The Coolant temp does go above 30C when under constant load with no overclock - Got as high as 35C which supports your statement about the coolant temp increase. Haven't tried it yet with an overclock. I believe I may have some misguided expectations for water cooling. I always thought it would run cooler so you could support higher clock speeds (and vCore now that you point it out) but it seems to me from what I've learned so far that the point of water cooling is essentially to be able to maintain higher clock speeds not necessarily achieve higher clock speeds since the media for heat transfer is larger on a water cooler than most tower heatsinks. Am I understanding correctly?

 

Here are the vCore numbers you requested. This is at 4.7 GHz and 5 GHz.

The 90C temps only hit at 5 GHz.

Assuming you haven't delided your CPU your temps are "perfectly" fine. You should be hitting 90's in heavy stress apps. Try a blender or a cinebench.

 

Other than that you could actually lower your voltages a bit, cause you are running too high. You should hit 5ghz with around 1.3volts, and if it doesn't, don't bother. There is no point going to 1.35 or more volts for 100 mhz, just settle for 4.9.

 

Mine was doing 5.1 @ 1.33v. Now "upgraded" to 10900k ;P

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Thank you for your replies and detailed instructions.

 

I set it up according to c-attack's instructions and now the system spikes to 80C. Definite improvement. My next question is, is this temp okay for this processor? Also, what is a good stress testing software for CPU's? I'd like to see what the temps are like after 15-20 minutes of load.

 

Thanks again for your help!

 

Edit - The LLC max was 7 and I set it to 5.

935246155_LoadvCore5.0GHzc-attacksettings.thumb.png.ccaba9d1b199dafe2d134ccbbb05c2be.png

Edited by TheDiagGuy
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I think 80C is spot on for most people at 5.0 on 8700K without a delid.

 

As for stress testing, it depends on what you are looking for. Programs like AIDA and OCCT in their normal form are testing stability more than thermal load. You will see a lot of up/down cycling of the temperatures. I prefer the CPU Linpack test in OCCT for testing thermals. Even more simple is the "bench test" in CPU-Z. It is a linear load and what I recommend for people investigating cooler issues. It's also very easy to spot how coolant temp and CPU temp change together since the load is flat.

Edited by c-attack
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