1U i9-9900k cooling in a Supermicro chassis

cuddylier

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Hi

I currently run an i9-9900k in a Supermicro SC813MFTQC-350CB chassis with motherboard X11SCZ-F and a Dynatron K129 heatsink however the cooling is far from sufficient and it's easy to get the CPU to overheat and throttle when you go above the 3.6GHz base clock with turbo.

Does anyone have any suggestions for better cooling for a 1U without having to look into 2U chassis to allow bigger heatsinks? I believe the CPU power usage is around 150 - 160W at max load and max turbo, the heatsink I'm using is only rated for 95W TDP but works fine with an i7-8700k at max load and max turbo (probably a fair bit less than 150 - 160W but still has a 95W TDP like the i9-9900k is).

Thanks
 
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Spartacus

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The 9900k is know for its heat especially when overclocking, even the luckier chips are space heaters.
Not alot of options unfortunately unless you can get a custom water loop low profile waterblock and run the cooling out of the case.

Delidding and a copper IHS might get you a bit of extra wiggle room, but overall its just the 1U cooling capability limitation.
 

cuddylier

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The 9900k is know for its heat especially when overclocking, even the luckier chips are space heaters.
Not alot of options unfortunately unless you can get a custom water loop low profile waterblock and run the cooling out of the case.

Delidding and a copper IHS might get you a bit of extra wiggle room, but overall its just the 1U cooling capability limitation.
I feared that would be the case. Water cooling within the chassis itself may have been a consideration but it's a non starter to run anything outside the chassis unfortunately (assuming that's what you meant).

I guess I need to look into heatsink solutions for 2U, if you happen to know some general solutions that would work in 2U then feel free to let me know, assuming that 2U is even enough.
 

Spartacus

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Correct outside the chassis is what I was referring.

The 2u coolers I think you can get up to 205w TDP heatsinks (and active vs the passive 1u) which while would be loud af would likely get you better results.
 

cuddylier

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Correct outside the chassis is what I was referring.

The 2u coolers I think you can get up to 205w TDP heatsinks (and active vs the passive 1u) which while would be loud af would likely get you better results.
Thanks, I'll look into the 2U options.

I found this water cooling solution for 1U which claims to support up to 260W, https://www.dynatron.co/product-page/l3. I don't believe it would be suitable for my chassis though, it seems aimed at the short depth non hotswap Supermicro chassis.
 

Deslok

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Supermicro is willing to/capable of craming a pair of 8280 xeon's in 1u so cooling a 9900k in 1u is technically feasible the bigger issue is getting the right heatsink. Most stuff with that kind of power budget in 1u is server sockets not LGA1151 like the 9900k.
That water cooler is actually a pretty solid solution if you can find it available for purchase, dynatron lists it as 1u and up so it should fit anything you can find space for the radiator.
 

BlueFox

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Oct 26, 2015
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Part of your problem might be the airflow offered by the fans on your chassis. You have the 40x28mm ones and I'm fairly certain different 1Us with 40x56mm ones would be able to cool your CPU with a heatsink that has sufficient fin density.
 

cuddylier

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kapone

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May 23, 2015
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Hi

Does anyone have any suggestions for better cooling for a 1U without having to look into 2U chassis to allow bigger heatsinks? I believe the CPU power usage is around 150 - 160W at max load and max turbo, the heatsink I'm using is only rated for 95W TDP but works fine with an i7-8700k at max load and max turbo (probably a fair bit less than 150 - 160W but still has a 95W TDP like the i9-9900k is).

Thanks
I'm confused. That CPU has a 95w TDP. How can it consume more power than that?? A 95w rated passive heatsink with enough airflow should be perfectly adequate. Whether it'll be silent or not is a separate issue.

Your problem is most likely those 28mm chassis fans, not the heatsink. Have you tried ducting the fans to the heatsink?
 

cuddylier

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I'm confused. That CPU has a 95w TDP. How can it consume more power than that?? A 95w rated passive heatsink with enough airflow should be perfectly adequate. Whether it'll be silent or not is a separate issue.

Your problem is most likely those 28mm chassis fans, not the heatsink. Have you tried ducting the fans to the heatsink?
The TDP is the power consumption when all cores are running at the base clock, it doesn't include turbo speeds. I believe this CPU gets up to around 150W with max turbo and load on all cores.

I haven't tried moving the fans from their stock position in the chassis yet.
 

kapone

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May 23, 2015
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The TDP is the power consumption when all cores are running at the base clock, it doesn't include turbo speeds. I believe this CPU gets up to around 150W with max turbo and load on all cores.

I haven't tried moving the fans from their stock position in the chassis yet.
Ummm...No.

TDP is TDP is unless you're overclocking. It cannot consume more than that.

I didn't mean move the fans, I meant an air shroud that directs airflow right at the heatsink inlet. Like this:

Supermicro-SYS-5019C-MR-Mellanox-25GbE-NVMe-SSDs-and-Air-Shroud-Installed.jpg
 

cuddylier

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Ummm...No.

TDP is TDP is unless you're overclocking. It cannot consume more than that.

I didn't mean move the fans, I meant an air shroud that directs airflow right at the heatsink inlet. Like this:

View attachment 11721
Interesting. I also run an i7-8700k server with this exact same config, it's also 95W TDP but it has no issues running full load so I figured the issue with the i9-9900k was because it was using more power when at full load versus the i7-8700k.

I haven't tried a shroud but I'll look into one, thanks.

Edit: I did some more research on TDP, everywhere suggests it is only for the base clock and turbo would go over the TDP e.g. Why Intel Processors Draw More Power Than Expected: TDP and Turbo Explained
 
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Deslok

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Ummm...No.

TDP is TDP is unless you're overclocking. It cannot consume more than that.

I didn't mean move the fans, I meant an air shroud that directs airflow right at the heatsink inlet. Like this:

View attachment 11721
Intel allows a cpu to exceed it's TDP under turbo if there is thermal headroom and the mainboard manufacturer allows it. However without overclocking a CPU(especially on a supermicro board since they stick to the letter of the spec typically) won't sustain a power above the TDP for an extended time.
Why Intel Processors Draw More Power Than Expected: TDP and Turbo Explained
 

cuddylier

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I just found The Intel 9th Gen Review: Core i9-9900K, Core i7-9700K and Core i5-9600K Tested which states i9-9900k power usage at max load (turbo only, not overclocked) is 168.48W so that's quite a lot to cool versus the TDP of 95W.

i7-8700k in comparison only gets to 86.21W (The AnandTech Coffee Lake Review: Initial Numbers on the Core i7-8700K and Core i5-8400) for a TDP of 95W at full load so that explains why my current cooling solution works fine for the i7-8700k and not the i9-9900, the i9s power usage is nearly double that of the i7.
 
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kapone

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@cuddylier - that's what I meant. "All core turbo" is overclocking.

I doubt your Supermicro board allows you to set all core turbo, does it?
 

kapone

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May 23, 2015
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Well, that explains it. With All Core turbo, TDP goes out the window. And in a 1U chassis...that CPU is gonna be real tough to cool acceptably.

Sorry, I hope I didn't mislead you.
 
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