Question Overheating i9-9900k even before overclocking, please help.

[kluky]

I'm trying to overclock my system, but even at 3.6Ghz when I run Prime95 I'm hitting temps in the mid 90's in under a minute. I tried both the newest version and 26.6. I've tried setting all fans and the pump to max speed. I've drained the system, removed the waterblock, cleaned everything with isopropyl alcohol, and applied new thermal paste (had Thermal Grizzly Kryonaut first, and now Arctic Silver 5).

My cooling loop includes the following in order:
EX-XRES D5 pump/reservoir combo
Gigabyte Aorus RTX 2080ti Waterforce WB
Hardware Labs Black Ice Nemesis 360GTS radiator with 3 120mm Noctua NF-F12 iPPC 2000 IP67 PWM fans
EK-Velocity Waterblock
Hardware Labs Black Ice Nemesis 280GTS radiator with 2 140mm Noctua NF-A14 iPPC-2000 IP67 PWM fans as well as 2 200mm case fans in a push pull config

In addition to the above my hardware includes:
i9-9900k
Gigabyte Aorus z290 Master motherboard
Corsair HX1000 PSU

I'm not sure what to try next. When I was building it I honestly thought I was going overboard on cooling. Can anyone give any suggestions?

 

[rubix_1011]

I use Prime95 26.6 for all my cooler testing here on the site.

I personally have an i7 9700k and GPU that is fully watercooled:

EK block
EK D5 pump/res combo
dual PE240 radiators
4x Vardar 120mm fans
EK full cover block for my RTX 2080
EK fittings

I just ran Prime95 26.6 and saw temps between 57C and 60C running for 5 mins. (stock settings, didn't touch AVX manual settings, etc, Small FFTs)

I just ran Prime95 29.5 rev6 - getting between 65C and 70C running for 5 mins, AVX is not disabled, small FFTs (checkbox is clear).

1. Are you setting AVX on or off during testing?
2. What are your idle temps?
3. 3.6Ghz is factory clocks, correct? And you see 90C at those settings, not OC, right?
4. Are you 100% certain the CPU block has good flow? I actually had my CPU block insert rotated 90 degrees when I changed the jet plate on mine and it was restricting flow almost completely. Disassembled the block, fixed it, been good since.
5. Do your temps immediately drop from 90C back down to idle within like...a 10 seconds, or is it very slow to creep down?
6. Does your radiator get warm or hot?
7. Do your CPU temps fluctuate up and down around the 90C mark, or do they continuously climb and stay there under load? Normally, you will see CPU temps pop up and down 1-2C once you reach thermal equilibrium.
8. What are you using to monitor temps?

 

[kluky]

1. Are you setting AVX on or off during testing? They were on for the newest version of Prime95 and load was being capped at around 75%. That's why I tried 26.6 - No AVX. 100% load but same temps
2. What are your idle temps? 34-37 degrees
3. 3.6Ghz is factory clocks, correct? Yes And you see 90C at those settings, not OC, right? Yes, under load, but not OC. But not much higher OC (although I stop the test pretty quick in either case)
4. Are you 100% certain the CPU block has good flow? I actually had my CPU block insert rotated 90 degrees when I changed the jet plate on mine and it was restricting flow almost completely. Disassembled the block, fixed it, been good since. I thought I put it together the same way when I swapped the jet plate but I suppose this is possible. The system seemed to prime quickly when filling though which would suggest good flow. I'll take a look tomorrow.
5. Do your temps immediately drop from 90C back down to idle within like...a 10 seconds, or is it very slow to creep down? Very quickly
6. Does your radiator get warm or hot? I can't really touch them directly due to my setup but the air blowing through them is definitely cool
7. Do your CPU temps fluctuate up and down around the 90C mark, or do they continuously climb and stay there under load? Normally, you will see CPU temps pop up and down 1-2C once you reach thermal equilibrium. The temps climb quickly so I don't think I really reach equilibrium as I stop the test too soon.
8. What are you using to monitor temps? Core Temp

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[rubix_1011]

OK, all your responses seem in line with what I would expect for a good setup. One thing to remember is that Prime95 is a synthetic loading virus; essentially it is meant to overload your system as much as possible, but this is less indicative to actual real-life scenarios.

If your loop primed and filled easily, then I would say you don't have an issue with the jet plate like my moronic self had (read the manual, didn't validate the orientation of I/O ports...sheesh). I assume it is easy to see flow in your reservoir due to a visible amount of turbulence?

So......

You are way overkill on radiator space, which is perfectly fine, you are in great shape, there.

Temps react quickly when you stop load testing, dropping quickly, so that's good. Temps climb quickly and seem to just rocket quickly into the stratosphere?...........almost seems indicative of incomplete CPU block seating on the IHS of the CPU. I mean, my system right now is idling at 30C and when I load it up on Prime95, it climbs 10C immediately, then coasts up 1-2C every 5 seconds or so until it hits the temp marks above and just sticks.

I've heard people say that 9900k chips are very hot running, which seems rather different than my 9700k which really should be similar other than lack of hyperthreading. (8 CPU cores) However, I personally haven't used a 9900k, so I might be very wrong.

You could also try checking load temps with HWinfo...that's a pretty comprehensive suite of tools. Another item could be checking if the BIOS of your motherboard has an issue reporting correct CPU temps...there have been well-known issues in years past about this, but may or may not a dead end. Is your MB a Z290 or a Z390? Only reason I ask is I think CoffeeLake is only z390, but I could be wrong, although Wikipedia seems to agree: https://en.wikipedia.org/wiki/Coffee_Lake#Chipsets

 

[kluky]

Sorry, yes, it's a Z390 board. That was a typo. I'm running the latest BIOS for this CPU I think you're right about a potential problem with the chipset. I got an RMA from Newegg so hopefully that fixes it because I am at a loss as to what to try next. Thanks for your help.

 

[Karadjgne]

https://www.anandtech.com/show/14047/the-gigabyte-z390-aorus-master-motherboard-review/8

Just some things about the board, it's a good read. If cpu vcore isn't being reported correctly, it's entirely possible it's way higher than it should be, which'll drive load temps through the roof.

Since it's the board that contains the bios, doesn't matter if the article is using a 8700k, everything else will be roughly the same.

Might just need tweaking to get all the ducks in a row.