[SOLVED] H100i V2 can't keep 7700k under 95 degrees, so...help?!?!

[Wesley_16]

With so much time on my hands from the quarantine, I thought I might finally attempt to overclock my 7700k, which some say can make it all the way to 5Ghz. After all, I have a motherboard built for doing crazy <Mod Edit>, and a H100i V2 liquid cooler mounted on the front of my computer. So I ran Prime95, with no overclock, and immediately my CPU temps went up to 98-99 degrees. Very bad, right? I let my pump cool off, to around 32 degrees C, with the CPU at 36 degrees, the temps my computer usually is at while idle. Turned up the pump to "Extreme" in Corsair iCue, around 3000RPM, and the fans to "Extreme" too, around 2000RPM.

Even with only 4 threads selected in Prime95, the temperature still shot to 95 degrees with all the fans/pump running at max. I even reseated my CPU with new thermal paste, and same temps. I've read that the 7700k can be a hot chip, but shouldn't a H100i V2 be able to handle that? I'm at a loss for why my cooler is performing so badly.

If it's worth noting, I do live in a rural area where lots of dust floats around in the air, so it's possible this could have clogged the radiator somehow, though I have dusted it and gotten most of the visible dust out.

I'll attach the rest of my build below, in case it can provide any other insight into why my computer is so masochistic:
CPU: Intel Core i7-7700K 4.2 GHz Quad-Core Processor
CPU Cooler: Corsair H100i v2 70.69 CFM Liquid CPU Cooler
Motherboard: MSI Z270 GAMING M5 ATX LGA1151 Motherboard
Memory: G.Skill Trident Z 16 GB (2 x 8 GB) DDR4-3200 Memory ($82.99 @ Newegg)
Storage: Samsung 960 EVO 250 GB M.2-2280 NVME Solid State Drive
Video Card: MSI GeForce GTX 1070 8 GB Video Card
Case: Fractal Design Define R5 (Black) ATX Mid Tower Case
Power Supply: EVGA SuperNOVA G3 650 W 80+ Gold Certified Fully Modular ATX Power Supply

 

[dmorisette]

I'm guessing that cooler is blowing out of the front? In that case it is using interior air that is pre-heated by that 1070 card. I would also guess that you have one exhaust fan on the upper rear? If you can, move the cooler to the top, blowing out. It's now working in tandem with that rear fan. Now install a pair of high flow 140s blowing in the front. this should totally solve your problem. My favorite is the bequiet Pure Wings 2 PWM 140mm High Flow model. around $13 each on Amazon. The standard version turns around 900 rpm at max and flows decent air and is totally silent. The High Flow version turns around 1600 rpm at max and flows a metric s**t-ton of air. It does make some noise though, you start hearing it around 1200 rpm or so and it gets progressively louder as speed ramps up. But it's not that objectionable.
If you plug these babies into your mb you can now have fun tuning your air flow/temps. I'm able to keep a 9700k (cooled via H100i Pro) & 2070S cool with a similar setup with all cooler settings on Balanced and front fans turning around 1200 revs. (While running both CPU and GPU jobs on FAH.)
Have fun!

 

[CompuTronix]

... 7700k ... H100i V2 ... Prime95 ... no overclock ... 95 degrees with all the fans/pump running at max ... new thermal paste ... gotten most of the visible dust out ... Fractal Design Define R5 ...

What was your ambient (room) temperature?

Which version of Prime95 did you run?

Which torture test did you run?

What is your AVX Offset?​

Advanced Vector Extension (AVX) Instruction Sets were introduced with Core i 2nd Generation CPUs, then AVX2 with 4th Generation. Prime95 versions with AVX enabled impose an unrealistic 130% workload which can adversely affect stability and severely overload your CPU. Many 6th through 9th Generation motherboards address the AVX problem by providing “offset” adjustments (downclock) in BIOS. -3 (300 MHz) or more may be needed to limit Core temperatures to 80°C.

As per Intel’s Datasheets, TDP and Thermal Specifications are validated “without AVX”. In Prime95 versions from 27.7 through 29.4, AVX can be disabled by inserting CpuSupportsAVX=0 into the local.txt file, which appears in Prime95's folder after the first run. However, since Core temperatures will be the same as 29.8 without AVX, it's easier to just use 29.8. You can also use 26.6 which doesn't have AVX.

“Stress” tests vary widely and can be characterized into two categories; stability tests which are fluctuating workloads, and thermal tests which are steady workloads. Prime95 v29.8 Small FFTs (AVX disabled) is ideally suited for testing thermal performance, because it conforms to Intel's Datasheets as a steady 100% workload with steady Core temperatures. No other non-proprietary utility can so closely replicate Intel's thermal test workload.

Click on the AVX test selections that are not greyed out so that all three AVX boxes are checked, as shown above.

Utilities that don't overload or underload your processor will give you a valid thermal baseline. Here’s a comparison of utilities grouped as thermal and stability tests according to % of TDP, averaged across six processor Generations at stock settings rounded to the nearest 5%:

Although these tests range from 70% to 130% TDP workload, Windows Task Manager interprets every test as 100% CPU Utilization, which is processor resource activity, not actual workload. Core temperatures respond directly to Power consumption (Watts), which is driven by workload. Prime95 v29.8 Small FFTs (AVX disabled) provides a steady 100% workload, even when TDP is exceeded by overclocking. If Core temperatures don't exceed 80°C, your CPU should run the most demanding real-world workloads without overheating.

Here's the nominal operating range for Core temperature:

Core temperatures above 85°C are not recommended.

Core temperatures below 80°C are ideal.

CT ​

 

[Darth Sicaedus]

That is some awesome information. I am booking marking your post @CompuTronix.

 

[Lojack_Gaming]

So SOO very glad the dude at Microcenter convinced me not to buy the h100i and I got the masterbox nr600.. I knoiw this doesn't help much but from the reviews that case doesn't have good thermals.. watch a little bit on GN.. which might have triggered you to not buy that case... It does look cool though I guess :/