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H115i Struggling with Delidded 9900k


g-man318

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Hi guys,

 

I'm looking for some insight into if my H115i is working correctly with a new CPU and mobo.

 

I've had my h115i since 2016 and it's been cooling my 2600k @ 1.40v+ for the past couple of years and has been doing great - no complaints. However, I've just upgraded to a 9900k pre-binned and delidded by Silicon Lottery, paired with a Maximus Hero XI motherboard.

 

On stock + XMP settings it's already hitting 100 degrees, with the performance preset in Corsair Link 4. (Fans ~2800 rpm, pump ~3100 rpm) using Cinebench R20 and Prime 95 blend. Bearing in mind HWMonitor is reporting peak voltage here at a mere 1.2v

 

I know the 9900k is a hot chip - especially when OC'd and I'm fully aware that if possible a custom liquid cooling solution is recommended. There's clearly something up here though. I've also heard about lower temps than mine from higher voltages on non-delidded chips from smaller AIOs too.

 

From digging around reddit and these forums it seems that when temps are insane like this it's either a busted pump, or bad contact.

 

I've tried re-seating the pump several times with varying amounts of TIM (Arctic Silver 5, but I have some MX-4 on the way). The pump is connected to the CPU fan header on the mobo, and SATA powered. Since my warranty is long dead and I've tossed the box, I don't mind telling you that I've also tried the washer mod to no avail.

 

When re-seating the TIM has definitely made contact and pump/backplate both seem solid with no wobble when installed.

 

The unit seemed to be working fine, until replacing the mobo, CPU and memory - so unless it's died in the few hours it took to change everything out I'm stumped.

 

I've checked the pipes with my hand and one is hotter than the other, so I'm fairly confident the pump is working to some degree. One thing I'm unsure about is the coolant temp is maxing out at 37 degrees, even when the CPU is hitting 100. I don't remember checking coolant temps before this so I'm unsure what it should be getting up to with that amount of heat.

 

Any help would be appreciated - I'm almost considering upgrading to a 360mm cooler but would like to rule out a faulty unit first.

 

Extra things to note:

- BIOS is the latest

- Case is a 750d with plenty of space and plenty of air coming in.

- Radiator, fans and case dusted

- Room temp 21 degrees

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Coolant temp max at 37C rules out a dying pump or some kind flow issue. However, to asses the efficiency of what you’re doing now, you need a start/idle coolant temp pre-load. Your probably around 27C, but the gains in coolant temp are going to be tight so be exact.

 

A +60C coolant to cpu temp differential is pretty high. This could be a very slight contact issue or more often voltage/BIOS settings. If you’ve verified the Vcore is steady at 1.20 and not playing Asus tricks, then it does seem more like a contact issue.

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Thanks man, good to hear the pump sounds good. The idle coolant is sitting at 29C.2 at the moment, with a min of 28.0, and CPU sitting at 35-38C at idle.

 

Anything you can think of to help track down the contact issue? As far as I can tell it's screwed down tight and as evenly as I can. It's the exact same way I had installed on my z68 I used to have.

 

Vcore is reported max 1.199 in CPUZ under load, so I don't think it's anything the mobo would be doing strangely voltage wise.

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These chips do get really hot, although at stock stock and 1.2V I wouldn't expect it to hit much more than 75°C-80°C core temperature under stress tests. I only hit 100°C on some cores when overclocked to 5.2GHz on all cores under serious AVX stress loads and 1.4V with my H115i RGB Platinum in push/pull configuration that pulls cool air from the front of the case (that is a newer cooler than yours, though, and thus possibly beefier), for example while I hit around 81°C maximum at 5GHz and 1.26V, 88°C at 5.1GHz and 1.32V. I'm using Thermal Grizzly Kryonaut paste, though and my CPU isn't delidded as it's soldered anyway.

 

Curious, what did you replace your 9900K's solder between die and heat spreader with? Or did you just leave it delidded and have the cold plate contact directly with the die? Did you lap it as well? There might have been some problem with the delidding process or the application of the thermal compound instead of the solder.

Edited by Glzmo
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This is more what's expected and from looking around on various reviews and tests seems to be more in line with what I'd want.

 

The delid was done by Silicon Lottery and they use Thermal Grizzly Conductonaut. The chip was binned and tested at 5.0GHz stable at 1.3 Vcore on a maximus board I believe.

 

If I can't lock down a contact issue or fault with my cooler I'll have to drop them a line.

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Yeah, I don't like the coolant/CPU difference at all. It is out of spec for a stock chip and most certainly for a delid. There are no miracles on a 9900K like the 8700/8086, but I have a Silicon Lottery 8700K and I think they do their work properly. It is possible the delid is not perfect, but I would not promote that as likely.

 

Your coolant delta of +8C is about what I expect and consistent with other people I know with 9900K, 5GHz, and a H115i pro or platinum. Also look at the data below from another user and his H150i. This is just so you can compare. His load is a 15 minute AVX video encoding run. He also goes, +8C on coolant. 280 vs 360 is going to very similar in terms of the maximum possible watt dissipation. However, the big difference is the required fan speed. You need those 2x140 blasting to reach the mark. With the H150i, you can park the 3x120 at a reasonable 1200 and get essentially the same cooling. This is the big advantage of a 360 in comparison, although it only become evident when you start to get into the 200-300W range.

 

Hardware: 9900K 5GHz all cores ~1.32V, H150i pump

Initial Liquid Temp ~28C

Pump Speed 2800RPM fan speeds 1600RPM: Liquid temp 36, CPU package temp 81

Pump Speed 2800RPM fan speeds 1200RPM: Liquid temp 37, CPU package temp 83

 

Also note the standard 9900K above at 5.0 has a liquid to CPU package differential of about 45C, and this one is at 1.32v! You should be down around the +40C mark, at worst and that puts you into the upper 70s at load.

 

I don't want to tell you to go get a new cooler. However, everything about the H115i Pro or H150i Pro is better than the prior model H115i. I have zero affection for that specific model. I don't see a cooler issue, but then something clearly isn't right. For you to go to Silicon Lottery and question the delid, you'll need to have all other causes rooted out. A 360mm radiator in the top of the 750 might make your life better (you do lose the top drive bay with this) and give you a better product, with a new backplate, and reduced noise at load. Something to consider. One other thing, you mention a "2800 rpm" fan speed. The H115i stock fans should max out at 2000 rpm. Did you put something else on there? AF-14i@3000rpm? That of course would make all of this even worse.

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I realised that I had misread that fan speed and was actually sitting at 2280 rpm, good spot!

 

Thanks for the help man, I'll give it a couple more re-seats when the mx-4 gets here as I've run out of paste now. I'd heard about someone rotating their block 90 degrees and it fixing their contact issue - I might give that a try on the off chance it sorts something.

 

If none of that solves it, I'll take the plunge and get an h150i, the idea of similar cooling power at lower rpm is attractive as I do intend to push the chip. If that's still not doing it I'll get through to Silicon Lottery and get them to check the delid.

 

Will update here.

 

Cheers!

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Alright, I made some progress!

 

I re-seated with some MX-4 and the temps dropped to 77C in Cinebench R20 on stock settings. That's almost a 25C drop! I had realised that the Arctic Silver 5 I have been using was bought way back in 2010, probably past it's shelf life.

 

I applied an OC to 5GHz tonight and it was still hitting 100C on Cinebench and Timespy, which was discouraging. I re-seated again, using the washer mod and I'm now maxing out at 95C in CB and 89C in Timespy at 5GHz. Perhaps there's something different about the fit seeing as my H115i is an older model, which requires the washers to get better contact.

 

I'm going to try dropping my voltage and backing off on the AVX offset to see if I can squeeze more performance during AVX loads out of this one.

 

Although this is totally usable, I'm going to upgrade to the H150i anyways - hopefully there's a difference in temps but I'm really after the reduction in fan noise.

 

If anybody is interested I can update here once the new cooler is installed, but if not, thanks for all the help here - you've literally saved hours/days in testing.

 

Cheers!

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  • 3 weeks later...

OK so quick update - it seems as though my cooler may have been borked after all.

 

I installed the h150i tonight and under a 5GHz all core OC I'm maxing out at 78C in Cinebench and much lower in Timespy and Firestrike. It's also quiet as a mouse, much better than fans ramping to full speed as before. This is at 1.27 VCore.

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