Description

An aggressive thermal solution and absolute fps gain

Here is my thermal calculation for CPU/GPU AIO Intake

1. At ambient 20 °C, air density is 1.2041 kg/m³, air heat compacity is 1005 J/kg.°C
2. The airflow of a 140mm Noctua NF-A14 is 140.2 m³/h, the airflow of a 120mm Noctua NF-F12 is 93.4 m³/h
3. The power draw of a 5.2GHz overclocked 8700K at full load with Prime95 AVX0 is 225W
4. The power draw of a 2.0GHz overclocked 1080Ti at full load with 3DMark Ultra is 350W

It all starts with a question:
For CPU AIO intake alone, how much heat will rise if the CPU is doing a Prime95 test?
The heat of CPU is dissipated by a 280mm AIO cooler.
And the calculation is

225J/s ÷ ( 1005 J/kg.°C × 1.2041kg/m³ x 140.2 m³/3600s x2) = 2.387°C

The result is 2.4°C more heat dumped into the case when doing Prime 95 with an overclocked 225W 8700K CPU. And of course, the CPU is delidded. And the motherboard components such as VRM would be 2.4°C hotter, though the VRM tolerance is above 100C. And for a good motherboard such as Asus Apex, the VRM is well under 80°C during Prime 95.

For 1 GPU AIO with a 120mm intake, the heat generation will be

350J/s ÷ ( 1005 J/kg.°C × 1.2041kg/m³ x 93.4 m³/3600s ) = 11.148°C

So it will be 11.2°C hotter for the motherboard under full load with max power draw

And for multi GPUs AIO intake setup, the heat generation will still be

N x 350J/s ÷ ( 1005 J/kg.°C × 1.2041kg/m³ x 93.4 m³/3600s x N ) = 11.148°C

No matter how many GPUs set as intake, the heat rise will be the same 11.2°C

So doing the CPU plus GPUs AIO intake setup, the overall VRM temperature would be roughly 14°C hotter under full load or under stability test such as Realbench (actually 8°C. Because the radiator and fan can't dissipate all the heat generated by the die on the CPU from that small surface area. And GPU power isn't maxed out in Realbench ). Plus this is not a daily load.
But if doing the N GPUs and CPU AIO as an outtake setup, it needs as much as 2X140mm and NX120mm equal intake airflow to reach the same cooling effect. To this point, not many cases are able to mount enough fans so the CPU and GPU will be a daily hotter compared to the intake setup.

I have been using intake setup for 6 months to do many torture tests and hit some benchmarks, plus 3 months of mining, the system is stable without a problem and I didn't shut it down for 6 months, motherboard VRM is well under 70°C. Btw, the exhaust fan is running at 100%, and other intake fans spin at least 80% regardless, so yeah, it is not a quiet setup.

As for dust concern, since the airflow is high enough plus the dust filter is available, there isn't much dust accumulated on the back of the GPU. It is even better than my previous normal empty intake fan setup.

Here are some of my benchmark videos with this machine. I have compared some X299/X99 HEDT gaming performance with different CPUs. 8700K is strong, in most cases straight up beating 6950X and 7960X. Can't deny It is currently the best CPU for gaming.

core components

CPU Intel - Core i7-8700K
Motherboard Asus - ROG MAXIMUS X HERO
Thermal Compound Thermal Grizzly Conductonaut
Memory Corsair - Dominator Platinum 64GB (4 x 16GB) DDR4
Video Card EVGA - GeForce GTX 1080Ti FTW3 HYBRID
Power Supply EVGA - SuperNOVA T2 1600W
Case Corsair - Air 540

benchmark scores

3DMark overall graphics Graphics Test 1 Graphics Test 2 Physics Test Combined Test
Fire Strike 36838 59994 295.27 fps 233.61 fps 73.35 fps 57.06 fps
Fire Strike Extreme 25250 30210 162.9 fps 110.03 fps 73.72 fps 55.93 fps
Fire Strike Ultra 14464 15173 86.6 fps 53.28 fps 73.57 fps 35.14 fps

Prime95 CPU performance - Min/Max FFT 1344

Core Clock Cache Clock Core Voltage Max Temperature Power Draw
5.1GHz 5.0GHz 1.37V 63°C 210W
5.2GHz 5.0GHz 1.42V 69°C 225W

8K GPUs performance

GPU Position Core Clock Memory Clock Core Voltage Core Temperature Memory Temperature Power Temperature Real Power Target Power Draw Max Power Spike
Top 2.0GHz 6.0GHz 1.065V 50°C 58°C 68°C 127% 350W 450W
Bottom 2.0GHz 6.0GHz 1.065V 52°C 60° 65°C 127% 350W 450W

Part List / Completed Build

Type Item Price
CPU Intel - Core i7-8700K 3.7GHz 6-Core Processor $347.89 @ Amazon
CPU Cooler Corsair - H110 94.0 CFM Liquid CPU Cooler $154.11 @ Amazon
Thermal Compound Thermal Grizzly - Conductonaut 1g Thermal Paste $25.00
Motherboard Asus - ROG MAXIMUS X HERO ATX LGA1151 Motherboard $257.57 @ Newegg Marketplace
Memory Corsair - Dominator Platinum 64GB (4 x 16GB) DDR4-3000 Memory $800.00
Storage Samsung - 850 EVO-Series 120GB 2.5" Solid State Drive $86.95 @ Newegg Marketplace
Storage Seagate - BarraCuda Pro 6TB 3.5" 7200RPM Internal Hard Drive $219.22 @ Amazon
Storage Seagate - BarraCuda Pro 6TB 3.5" 7200RPM Internal Hard Drive $219.22 @ Amazon
Storage Seagate - BarraCuda Pro 6TB 3.5" 7200RPM Internal Hard Drive $219.22 @ Amazon
Video Card EVGA - GeForce GTX 1080 Ti 11GB FTW3 HYBRID GAMING Video Card (2-Way SLI) $799.99 @ Amazon
Video Card EVGA - GeForce GTX 1080 Ti 11GB FTW3 HYBRID GAMING Video Card (2-Way SLI) $799.99 @ Amazon
Case Corsair - Air 540 Silver ATX Mid Tower Case $147.72 @ Newegg Marketplace
Power Supply EVGA - SuperNOVA T2 1600W 80+ Titanium Certified Fully-Modular ATX Power Supply $369.00 @ Amazon
Case Fan Noctua - NF-F12 PWM 55.0 CFM 120mm Fan $19.50 @ Newegg
Case Fan Noctua - NF-A14 PWM 82.5 CFM 140mm Fan $21.75 @ Amazon
Case Fan Noctua - NF-A14 PWM 82.5 CFM 140mm Fan $21.75 @ Amazon
Case Fan Noctua - NF-P14s redux-1500 PWM 78.7 CFM 140mm Fan $14.95 @ Amazon
Case Fan Noctua - NF-P14s redux-1500 PWM 78.7 CFM 140mm Fan $14.95 @ Amazon
Case Fan Noctua - NF-P14s redux-1500 PWM 78.7 CFM 140mm Fan $14.95 @ Amazon
Case Fan Noctua - NF-P14s redux-1500 PWM 78.7 CFM 140mm Fan $14.95 @ Amazon
Case Fan Noctua - NF-P14s redux-1500 PWM 78.7 CFM 140mm Fan $14.95 @ Amazon
Other Intel Optane SSD 800p Series (118GB, M.2 80mm PCIe 3.0, 3D XPoint) - SSDPEK1W120GAXT $198.94 @ Amazon
Prices include shipping, taxes, rebates, and discounts
Total $4782.57
Generated by PCPartPicker 2018-07-24 18:17 EDT-0400

Comments

  • 12 months ago
  • 4 points

Engineer spotted

  • 12 months ago
  • 2 points

My thoughts too.

Real passion!

[comment deleted by staff]
  • 12 months ago
  • 3 points

Did you De-lid your CPU ? Especially the 8700k

All this thermal talk without doing that seems kind of silly no ?

  • 12 months ago
  • 1 point

Pretty crazy what a difference it makes. I knocked 20°C off my 6700k by replacing the awful thermal paste with liquid metal.

  • 12 months ago
  • 0 points

check my part List

  • 12 months ago
  • 3 points

Is the rear fan supposed to be set to intake? Doesn't match your diagram.

  • 12 months ago
  • 1 point

That photo is taken during test, I'll upload some later

  • 12 months ago
  • 2 points

Welcome to Thermodynamics 502. A little bit about me; I'm Mr. BattlePoop, been a teacher at PCPP University since '95. Class syllabus will be released on my class page. Grading scale is 99.99% tests, 0.01% homework and projects. There will be a final project and the end of the semester, due before finals week. Now onto the my lecture...

  • 12 months ago
  • 1 point

Were both the cards modified into hybrids? If so, any issue with installing the hybrid kits?

  • 12 months ago
  • 1 point

I'm the actually the first person who noticed the hybrid kit has potential problems. The installation process is complicated, the shroud can easily scratch components on PCB. But you can still successfully install it if being patient. The topic is quite popular on EVGA forum.

  • 12 months ago
  • 1 point

Yeah I was reading the horror stories about how the FTW3 hybrid kits were causing components on the PCB to short out and it was causing the cards to permanently lock to stock clocks. I emailed EVGA support about it just last week asking if they were aware of it and they actually responded and said they were aware of the issue and all the hybrid kits manufactured since Feb. have been fixed/revised.

  • 12 months ago
  • 2 points

It is not completely the fault of the kit. The complete installation usually takes 2 hours of each kit and people get impatient.

  • 12 months ago
  • 1 point

SORRY to just pop in. I was looking at EVGA Website and they dont have any Hybrids listed. Couple days ago they did. NOT out of stock, not listed at all. Maybe thats the last of em for the 10 series.

  • 12 months ago
  • 1 point

I meant GPU's. Sorry for the miscommunication.

  • 12 months ago
  • 1 point

Cool ;)

  • 12 months ago
  • 1 point

Very cool

  • 12 months ago
  • 1 point

Holy crap r/theydidthemath is leaking.

Lol, asides from all those calculations whooshing over my head, this is a great build!

Since you seem obviously knowledgeable on thermal capacity and calculations, is this SUPER-positive pressure setup better than a typical intake front/bottom and exhaust top/back?

Would it be better optimized to intake on bottom with GPU rads, intake from front with CPU rad, and exhaust out the top/back? Just my thoughts from my limited knowledge.

  • 12 months ago
  • 1 point

stay positive!

  • 12 months ago
  • 1 point

Notcua FTW ! ;p Looks like your exhaust fan is backwards, unless you changed your mind from that air flow diagram. Any reason you didn't do a custom loop ? :)

  • 12 months ago
  • 1 point

I like this. This is good. More of this.