Question Water Cooled 12900k package 100c gaming, 50-60c idle

pk1209

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Another thread about a HOT 12000k..

My water cooled setup is about 15 months old:
  • 12900k (AI optimized) with Corsair XC7 Block
  • 2 x 16 GB Corsair 5600mhz Dominator (XMP2)
  • Asus z690 Hero (the non fire one)
  • Asus Rog Strix 3090 with Corsair Water Block
  • Corsair XD5 Pump to 360mm RAD to GPU to CPU to 240mm RAD to pump
  • 8 case fans - 5 intake (3 front, 2 bottom), 3 exhaust fans (2 top, 1 rear)
  • All inside Corsair 680x
I had always planned on draining and re-applying thermal paste after about a year, and finally got round to it this weekend. When I first built this thing, CPU package was probably 15-20 degrees cooler in comparable situations (idle/gaming). I have a display on my keyboard with package temp, so monitoring was easy.

Tbh, I stopped paying attention because I knew temps were good, and just before the drain/refill I noticed that package was hitting 100c playing MW2 so that triggered me into action.

Drained and applied new thermal paste (Arctic MX6), replace a couple yellowing tubes and refilled with new coolant.

And basically, temps are exactly the same...

Idle voltage is 1.28 ish. I tried a 0.05 offset in BIOS, Windows Blue Screen. Tried 0.04, booted but MW2 was crashing, and before it did, temps where the same, so given up on undervolting, although I hear that the offset method is dodgy and maybe I should just set a manual undervolt?

Coolant is running around 35-36c when CPU package is 55-60c. So coolant seems ok?

Running pump and fans at full not making much difference either while gaming.

I have ordered a 12900 frame incase it's the CPU bending issue.. which I think could be involved given the steady rise in temps...

I know the CPU can handle getting this high, but this seems crazy for gaming on a water cooled loop!

What else should I be looking at? i have installed Intel XTU, but haven't tinkered... I'm no pro, and don't want to brick anything... (or force OS reinstall!)

Thanks!
 

Eximo

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Well you might be a little undersized when it comes to radiators, but still, shouldn't be hitting 100C. Idle CPU temp should be more like 25C.

I suspect you need to actually take apart the CPU block and inspect the microfins. Coolant mixes can gunk up and prevent flow. Could just need a good scrubbing with a toothbrush.

I always just go with distilled water and a small amount of biocide.
 

pk1209

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yeah, kinda kicking myself for not doing that when I drained the loop... to be fair, I need to get better at doing it as probably want to be draining and cleaning the blocks every 6 months or so. Is dismantling the block really necessary, or can I flush the gunk out with the water and biocide as you mentioned? (What biocide do you use out of interest?). Might even blow some air through the blocks with my air pump I use on the kids paddling pool :D
 

Eximo

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I would take it apart, usually pretty simple.

6 months might be prudent if you use a colored coolant, or one of those opaque ones.

The biocide I use is a Primochill product, can't recall the exact name. You can use tap water for cleaning it, even a little dish soap. Then you want to rinse with distilled water a time or two.

Then you either put in the distilled water and biocide, or use a pre-mixed or additive coolant. Coolant mixes are going to have biocide in them already, as well as corrosion inhibitors and anti-freeze properties.
 

pk1209

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Thanks - I did some googling, and I'm going to try Mayhems Blitz part 2 before I get into dismantling. I'll drain the loop, rinse out the blocks as best I can using distilled water and air (going in reverse to normal flow) then the Mayhem's part 2 followed by 4 distilled water flushes, them Mayhems x1 clear coolant. I'll fit the 12000k bracket somewhere in amongst all that... then we'll see what we have...
 

Roclemir

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I'll be honest, I briefed over your description but it does sound like what has happened to me in the past:

You haven't quite applied the thermal paste well enough and/or the cooler isn't secured tight enough.

Long story short, the heat is not transferring to your cooling rig. This is either caused by a too-thin layer of thermal paste and/or you haven't tightened the thermal pad onto the CPU enough.

Or, you messed up with connecting the cooler the first time so you pulled it off, then you tried to put it back on again without removing/reapplying thermal paste. When thermal place is applied, you only get one-shot at attaching the cooler and securing it, if you remove the cooler for any reason, you need to remove/reapply the paste so you done get bubbles or anomalies in the paste (yes I know sometimes people luck out and this doesn't happen but that is only luck). But from your description you sound like you know what you are doing so I doubt this is the problem.
 

pk1209

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yeah, the XC7 block is pretty straight forward. Fully cleaned the block, nice blob of MX6 in the middle of the CPU then doing the screw down a little bit at a time on each for the block... I'm gonna do next bits in stages. Unmount the cooler, fit the 12900k bracket, reapply paste and fit again and see what happens. Then, Mayhems part 2 clean and flush...
 

pk1209

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OK thermalright CPU frame fitted... definite improvement. 7-10 degrees on idle, still high at 48/49 but also not jumping around as much. Coolant holding steady on same fan curve about 4-5c cooler. Will see what MW2 throws up shortly...

EDIT - not really helped at all under load.... this thing has me so puzzled. I'm convinced this has come out the blue. I would have noticed it getting hotter and hotter. I'm almost wondering if it could be a CPU issue, temps are just inexplicably high... Looking at it now, 30c coolant and 70c package on 1% load.. what wtf. GPU on the same loop is fine, 30-35c at idle...
 
Last edited:
Hi
Would like to bring some attention to the CorsairXD5.

I had the Xd5 in my loop but pulled it and replaced it with a Ek Kinetics Tbe 300, after I recieved my alphacool flow/temp sensor because the xd5 running at the max 4800 rpm could only muster approx .5gpm flow rate, eventhough it is listed to do 800 L/h @ 2.1 pump head preasure.
My loop at the time was 420x45, - 280x60 alphacool low restriction rads, a Xc7 pro Wb on a 5900x, Evga 2080 ti Ftw3 with a Ek Quatum Vector Wb.
No matter how I set the loop order it stayed at approx .5gpm and my loop temp seemed good but the 5900x was always jumping straight to high 70's c when testing.
I contacted Corsair their response more less was it's not overheating and that the temps was adequate and wanted to convince me the flow rate was that of other D5 pumps.
I told them to quit PLAYING WITH BLING BLING TOYS and put Performance Back in the Corsair Brand.
That's when the Xd5 came out and the Ek Kinetic Tbe 300 ( 1500L/h 3.9 pump head ) went in along with a 360x30 as well, now my flow rate is over 1gpm and my cpu temp does not go up so quick.


In time when my son's H150i E C bites it , I will put the Xc7 pro on his 5600x( I just Bought a Optimus Foundation Wb for the 5900x ) throw in a 360mm and the Xd5 for a Cpu only loop, which it should do ok as we don't Oc the 5600x.
So it's not a total $160.00 mistake.


Good Luck !!!!!!!!!!!!!!!!!!!!
 

pk1209

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Well... I may have fixed it... There was a massive air bubble trapped out of sight at the top of the reservoir which I think was basically blocking flow... Whether that was also the issue before I drained the loop or not I don't know, that could have just been old coolant, new paste needed and some CPU bending... but since getting that air out, CPU package was hitting 80c instead of 100c in MW2 (was 1:30am by this point, so didn't do too much testing :D)
Might try cinebench now as well
 

pk1209

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Thanks - will take a look at a pump upgrade.... it's also the one corsair part that isn't visible in my system because of the dual chamber case, so the easiest to replace without messing RGB :D