are you able to increase the pump speed, likely the cpu is throwing out so much heat under load the loop isn't fast enough taking heat away and replacing with cool liquid.
tbh a overclocked 18 core cpu with hyperthreading will heat up very fast and no matter the cooling loop most will struggle, and if you can keep it around 75 degrees under load thats actually pretty good for such a high core count chip.
also worth noting your cpu block may be installed incorrectly, most x299 setups have the barbs side by side and usually the barb to the left is inlet and to the right is outlet, but the heatkiller block you have is slightly different try you block with inlet to the right and outlet to the left
install the block so the heatkiller writing is the correct way up like below
I agree that it's handling a lot of heat and there's a limit. But I'm not having luck keeping the temps as low as I'd expect even so. I'm getting high 80s (87-90 C) not under 75 C at all.
Granted its OC but still..... almost 60 C difference between reported package temp to water temp, when using one of the better blocks and compounds out there? That's kinda more than unexpected...
Pump speed:
I don't know if I can up the pump speed. 3.3 L/min (0.7 GPM) might be about right for a D5 on this simple loop?
Annoyingly the PWM and tacho were both dead on arrival (tried all baseboard connectors and wired PWM to +5v molex as a last resort which should be 100% duty cycle on PWM, none helped or changed speed up or down). But that said, 3.3 L/min (0.7 GPM) isnt totally unreasonable. Should a D5 could get much higher on this loop? It doesn't sound like it's idling at 40-60% as some pumps do. I could buy and try out a D5 vario for certainty, but does it sound likely?
Block orientation/connection:
Watercool's
instruction docs for the block state that
"The HEATKILLER® IV has no predefined orientation on the CPU. Depending on the mainboard layout, all four facings should be possible. Those are: logo left (vertical), logo right (vertical), logo on top (horizontal) and logo at the bottom (horizontal). The alignment of the cooler has almost no impact on cooling performance and may be chosen freely", and
"The intake is in the center of the cooler." (sections 3+10)
That's what I've followed. I just rechecked to make sure I did get it right. Intake is indeed centre and right now the PC case is moved with its back flat on the floor so there's no "up" or "down", motherboard and CPU are parallel to the floor. So orientation shouldn't matter and should be eliminated as a factor regardless? What do you think?
I would say its fine, a lot of heat in a small package and your block is as good as it gets.
As above try mounting the block goofy if still not happy whack another 480 rad on your board and up the pump speed.
I'm not sure another rad or faster water flow will add that much? If it was having trouble dumping heat
out of the loop, I'd expect to see higher loop temps compared to ambient.
But here I'm seeing water temps barely 6 degrees above ambient, but CPU temps a full 55-60 degrees above water temp. That suggests to me, that the issue is heat transfer at the cpu/block interfaces, not rad->air.
If another rad dropped the water delta T by say half, to say 27 C not 30C, or faster water flow dropped another couple of degrees in the water, the difference at the *block* end would be 58 C not 55 C - almost negligible, not enough to force much more heat transfer from the CPU.
Does that sound about right?
Is your m/b cpu in a case?
The board and CPU are in a case, but the case is *wide* open to ambient, and there are full-on fans blowing at the entire CPU/VR region. Full view:
Other/"exotic" options? (Speculative!)
I'm using Noctua NT-H1 at present ("thin spread" rather than "dot" due to the large size of the 2066 heat spreader: the die is central but every bit of contact helps?). One way to win a couple more degrees might be improving the thermal compound layer. Not really the bigger change I'm looking for though.
This article suggests an "X" shape instead for a tiny improvement. Another option I've read about might be Coollaboratory Liquid Metal Pad, a kind of metal leaf that melts into a thermal layer when first heated and is said tomwin a couple of.degrees over the noctua. (I won't try a fluid metal compound, too inexperienced to judge quantity on this size CPU).
Another option might be to peltier cool the water loop a bit, perhaps via the rad body itself near the inlets/outlets, where there's a large metal contact area, rather than the block, to take a bit more heat out than the rad alone can do, and maybe slightly chill it a little below ambient. Too much risks condensation but EPDM tubing is a pretty good insulator which works both ways, and if peltier+rad drops the water loop from 6 above ambient to maybe 5-8 below, perhaps that differentual will pull noticeably more heat from the CPU without risk to the system? (Most of the loop is outside the case and "condensation safe", see pics).
I guess both of these would take me into exotic cooling territory. Not usual for a 24/7 workstation. But if the issue is heat transfer from CPU package to water, as it seems, and I'm using a good rad and one of the better blocks/TIMs, is there anywhere else to look for a further 5+ C gain, without it?
Can I achieve much by say, doubling pumps, flow rates, rad "push" fans, or something else I'm missing?
Is it usual for there to be such a huge temp difference between CPU package and water temps if I've done everything correctly with good quality components?
