As I alluded to before, I have been working on solving a problem I experienced with the custom workstation I have built last year. That problem is heat. I solved it as per the photo below.

I did not realize it initially, but the heat generated by the two 1080 Ti cards coupled with the Phanteks Evolv case caused the two cards to thermal throttle pretty much for anything I do that uses GPU power. The GPU temperatures would quickly run up to 84˚C, and the cards would start dropping their clock speed to stay within the thermal limits. This basically nerfed the 1080 Ti cards' performance half way back to the 1080 I originally had. Kind of pointless to spend $2000 on an upgrade only to lose that advantage due to excess heat.

Initially I thought the way to solve this is to make use of custom water cooling. I ordered two 1080 Ti water blocks, an LGA-2011v3 CPU water block as well as one 240 mm and one 360mm radiator, with matching Vardar fans from EKWB. Naturally this included compression fittings, tubing (I decided to start with soft tubing) and coolant. It took some effort but I made all of that fit in the Phanteks Evolv case. The 240mm radiator was mounted in the front as an intake with push/pull fan configuration, and the 360mm was mounted on top as an exhaust. The rear of the case had one 140mm intake fan.

You can read more about that build here.

That case sure is pretty. But I must admit, I made one small omission in that document I linked to. The figures I got was only when I removed the front and top panels, and the dust meshes. See, this case is very pretty, but horrible for good airflow in a high powered build like this one. The panels are way too close to the fans to allow sufficient fresh air in and blocks air from leaving the case, causing it to recirculate. I even tried to mask off some of the internal baffles to no avail.

I was also not too happy with the lighting since the case is very crowded, blocking a lot of light from my aura LED light strip on the right hand side of the case. Time for a change...

After watching some of JayzTwoCents' videos I decided the CaseLabs SMA8 case is the way to go. One does not realize exactly how big this case is once you start to build it. Yes - you heard right. The case is flat packed from California after being custom built (and waiting for 9 weeks). Building it is slightly more difficult than Ikea furniture but easier than doing a custom water loop. Just be warned - although the case is awfully well built, fantastically modular and about as good as it gets, it is very expensive and CaseLabs' support sucks big time.

I acquired an additional 560mm radiator (4 x 140mm fans) and used that with the 240mm (2 x 120mm) in the bottom section. The 360mm (3 x 120mm) is mounted on top. So the 560mm is an intake, and the 240mm is an exhaust. That keeps the airflow direct and efficient in the lower section. I added 3 x 120mm Noctua fans in the front as intake, and 1 x 120mm in the rear also as intake. The 360mm radiator on top acts as the exhaust. This way I have positive air pressure in both chambers.

After fiddling with the issue of needing to hook up 13 fans and one water pump to my Asus X99 motherboard, fine tuning them and fiddling with overclock settings I finally managed to get to the following stable specifications:

• i7-6850K overclocked to 4.4GHz on all 6 cores at V_core = 1.35V
• DDR4 RAM using XMP profile at 3200MHz
• 2 x nVidia 1080 Ti Founders Edition in SLI with HB bridge overclocked to 2050MHz GPU clock speed

Running Prime95 (no AVX, small FFT) and Furmark at the same time does not even ramp up the fans audibly. The temperatures for the GPUs never exceed 56˚C, and the CPU never exceeds 66˚C on the hottest core. This permanently solved my thermal throttling issues.

Some additional performance figures for this system (with the noise level under 39dB 1m away from the PC, and ambient temperature of 24.8˚C):

There are some cons to this system. For starters, it weighs 30kg - not very portable. The case is huge - which is fine by me as it is supposed to be a center piece, however moving it around is a pain. And then there is the cost...

I did have it overclocked slightly more but decided to drop the CPU overclock by 100MHz in favour of getting temperatures lower and V_core away from 1.5V which was what was needed to make it work at that overclock. So all these results are from 4.4GHz.