Question i9 9900k 55c idle Custom Loop

Mar 5, 2019
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Not sure what to try next. Suggestions are welcome.

CPU: i9 9900k
COOLING:
- Ekwb Velocity cpu block.
- Ekwb gpu block.
- 2 Ekwb 360 rads (one slim one normal).

I’m reading 28-30 in BIOS stock config (38-40 OC), but once windows loads and I let it idle, the temperature settles around 47 stock (55 OC). Don’t know liquid temp but ambient is around 23-24.

For the OC I’ve stress tested with prime95 30 min, cinebench, and kombuster cpu burner for 30 and it's stable, max temp 83.

It doesn’t really hurt to let the cpu idle at 55 as long as load temps are under control , but I’d like get the most out of my cooling system.

My gpu idles at 27 and stays under 50 (OC) during stress tests, so I don’t believe the pump and/or fans are the issue.

I suspect it’s an issue with the contact between the block and cpu, but I’ve reseated it 6+ times to no avail. I’ve tried...
- two different pastes
- different application patterns
- screw tightening patterns
- retightened the mounting plate and screws.
- Cleaned the block itself

Other than sanding down the IHS, any ideas?
 
Last edited:

Lutfij

Titan
Moderator
Can you state the FPI/thickness of the rads you're working with as well as the fans that are on it? With watercooling, your temps will be reflected by the fans RPM, the thickness of your rads as well as the ambient air temps.

We'll also need your current system's specs. List them like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:

And the voltages you've got in BIOS set for your processor. In all honesty, from the top of my head, if my assumption is right with your watercooling gears flow rate and pump setup, you're in the right region in terms of temps.
 
Mar 5, 2019
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Thanks.

CPU: i9 9900k
Motherboard: MSI Z390 Godlike
Ram: 64 GB 3200 Gskill
SSD/HDD: Samsung 970 EVO 1TB - NVMe PCIe M.2 SSD
GPU: 2080ti FE
PSU: EVGA SuperNOVA 80+ Platinum 1000W
Chassis: Lian-li PC-O11
OS: Windows 10 Pro (Power settings ultimate performance)

My radiators and fans:
NOTE: I've plugged the pump into one of the sysfan headers, but I've set it to run at 100% (12v) PWM in BIOS. Also, my fans exhaust out over the radiators. I've set a custom fan curve, but I don't have the exact numbers with me at work, but they never run lower than 60% (1320rpm).

I don't have the stock voltage as I've left it OC for now. As for my OC settings (55 idle), I've favored some settings that result in greater power draw, so it's possible, as you mentioned, that my temps are expected.

OC BIOS Settings:
  1. CPU Ratio: 50 (All Cores -- Fixed Ratio)
  2. Ring Ratio: 47
  3. XMP Enabled (3200 MHz)
  4. Core Voltage 1.35 (Override Mode)
 

Karadjgne

Titan
Herald
With a 5.0GHz OC on a 9900k, things are gonna get warm, for sure. But you aren't at a true idle either. You are still at 5.0GHz and full vcore voltages even with limited loading, not what most consider idle where cpu drops to 800MHz and vcore takes a nose dive.

If you save your bios to a profile as is, then reset bios to factory defaults, you'll probably expect temps at idle to be much closer to 30°C if the block and paste are good.
 
Mar 5, 2019
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With a 5.0GHz OC on a 9900k, things are gonna get warm, for sure. But you aren't at a true idle either. You are still at 5.0GHz and full vcore voltages even with limited loading, not what most consider idle where cpu drops to 800MHz and vcore takes a nose dive.

If you save your bios to a profile as is, then reset bios to factory defaults, you'll probably expect temps at idle to be much closer to 30°C if the block and paste are good.
Unfortunately, I’ve tried doing that and while I get 27/28 in BIOS, idling in windows still jumps to ~47
 

Karadjgne

Titan
Herald
47°C after windows settles down to idle at stock settings? Ow. That's warm. Now is that a true(ish) idle? Or is there still stuff running in the background? If there's more than @ 5% cpu usage, you aren't idling. Bios temps are almost always higher than idle, so bios of 27/28 leads me to think your cpu really isn't getting to idle but is running 20-30%. Prolly anti-virus or windows shop updates or other background processes/services keeping you at a load state.
 

rubix_1011

Contributing Writer
Moderator
This might be a silly question, but many CPU blocks are unidirectional - if you don't set them up correctly, flow is restricted and can cause temp issues. I'm assuming your block inlet and outlets are correctly utilized?

If there is a directional jet plate used in the block, is it set correctly for flow? (I've actually accidentally done this incorrectly with the jet plate positioned 90 degrees too far and had nearly zero flow. Pulled the block, disassembled and corrected the jet plate, reassembled, remounted....worlds of difference.
 
Mar 5, 2019
6
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47°C after windows settles down to idle at stock settings? Ow. That's warm. Now is that a true(ish) idle? Or is there still stuff running in the background? If there's more than @ 5% cpu usage, you aren't idling. Bios temps are almost always higher than idle, so bios of 27/28 leads me to think your cpu really isn't getting to idle but is running 20-30%. Prolly anti-virus or windows shop updates or other background processes/services keeping you at a load state.
That’s a fair point. How do you/others define idle with regards to temp? Terminating all non-essential processes in task managaer then letting things settle? And what about power management settings, which surely impact thermals.
 
Mar 5, 2019
6
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10
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This might be a silly question, but many CPU blocks are unidirectional - if you don't set them up correctly, flow is restricted and can cause temp issues. I'm assuming your block inlet and outlets are correctly utilized?

If there is a directional jet plate used in the block, is it set correctly for flow? (I've actually accidentally done this incorrectly with the jet plate positioned 90 degrees too far and had nearly zero flow. Pulled the block, disassembled and corrected the jet plate, reassembled, remounted....worlds of difference.
I’ve disassembled the block twice and actually removed the jet plate since the last time I noticed very small debris (perhaps from dust or solder in rads) blocking flow. I didn’t notice much of a difference with/without this piece. The inlet (intake closer to center) is fed directly from the rad.

If I decide to reseat the block one last time, I’ll open it up and put it back in. I can’t imagine this making more than a few degree difference at best, but I could be wrong.
 
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Karadjgne

Titan
Herald
I've got an Ivy Bridge cpu, so it's slightly different to modern Haswell or newer cpus. But, essentially the same. If there's no user input after a specified time and there's no programs running that require windows full power, C-states kick in low power mode, the cpu drops to 1600MHz, vcore drops to 0.8v etc. But this'll only happen if there's between 5-9% or so cpu usage as seen by task manager. That's idle. For you with locked core/locked vcore/locked multiplier at 5.0GHz, idle will still be no user input, no programs running, 5-10% processes/services/usage in task manager. If you are seeing 20-30%, your cpu isn't idle. It's working. It has a load beyond basic windows pc normal apps. Bios is a full power state, the POST, constant communication with hardware, loading drivers and devices etc, all of that is a 40-60% load so if left in bios for half an hour to equalize temps, it should always be higher than idle. My bios, 45°C. My idle 32°C. So if your bios is 28°C after half an hour, and you idle at 55°C in windows, there's a load in windows that's not present in bios. Basically you have more running in background than basic windows stuff. Driver updates, Antivirus, blog feeds, news feeds, windows store updates, email services...

Something.
 
Mar 5, 2019
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I've got an Ivy Bridge cpu, so it's slightly different to modern Haswell or newer cpus. But, essentially the same. If there's no user input after a specified time and there's no programs running that require windows full power, C-states kick in low power mode, the cpu drops to 1600MHz, vcore drops to 0.8v etc. But this'll only happen if there's between 5-9% or so cpu usage as seen by task manager. That's idle. For you with locked core/locked vcore/locked multiplier at 5.0GHz, idle will still be no user input, no programs running, 5-10% processes/services/usage in task manager. If you are seeing 20-30%, your cpu isn't idle. It's working. It has a load beyond basic windows pc normal apps. Bios is a full power state, the POST, constant communication with hardware, loading drivers and devices etc, all of that is a 40-60% load so if left in bios for half an hour to equalize temps, it should always be higher than idle. My bios, 45°C. My idle 32°C. So if your bios is 28°C after half an hour, and you idle at 55°C in windows, there's a load in windows that's not present in bios. Basically you have more running in background than basic windows stuff. Driver updates, Antivirus, blog feeds, news feeds, windows store updates, email services...

Something.

Thanks, that makes sense (especially since I've disabled c-state). I'm going to do one last reseating of the cpu block tonight after I drain the system and put the jet plate back in. Any other tips or suggestions?
 

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