A simple fan mod that helps address additional heat from GK110 SLI primarily for those who wish to keep their case buttoned up with all of the filters and side-panel on.
Test Rig: i7 4930 and EVGA 780 Ti SC w/ACX SLI
Ambient ~73 F
Benchmark: Unigine Heaven 4.0, 1920x1080 DX11, AAx4, Tessellation: Extreme
GPU idle temps at beginning of test: 30-31 and 29-28 C primary and secondary GPU repectively.
GPU Fan Algorithm: 40% RPM idle, starting at 30 C ramping up to 100% RPM at 65 C with a linear trajectory.
Case Fan Algorithm: All PWM case fans at 60% RPM 30 C idle ramping up to 100% at 65 C based off of the CPU temperature with an exponential trajectory.
With no fan mod, side-panel on, top and front filter in place:
79 C primary 74 C secondary exactly at end of benchmark.
With fan mod, side-panel on, top and front filters in place:
74 C and 68 C at end of benchmark.
Without fan mod, side-panel on, top and front filters removed:
76 and 72 C at end of benchmark.
With fan mod, side-panel in place, top and front filters removed:
73 and 67 C by end of benchmark.
Without fan mod, side-panel, top and front filters removed:
71 and 65 C by end of benchmark.
Without fan mod, side-panel on, top and front filters removed and an aggressive fan algorithm (case fans increased from 60% RPM idle to 70% RPM):
73 and 69
With fan mod, side-pane on, top and front filters on and aggressive fan algorithm:
74 and 68 C (no difference vs. less aggressive fan algorithm meaning same performance with less noise with the latter configuration!)
And I haven't done the testing but I imagine that with a completely open case, i.e. side-pane and all filters removed, that this fan mod would still be beneficial.
Based upon the testing results it is apparent that there is no appreciable difference between having the filters on or off with this mod or with a more aggressive fan algorithm. This mod is ideal for those who wish to keep their case buttoned up and want to keep noise down. Positioning an exhaust fan on the back of the case behind the GPU's just makes sense; working in tandem with the front case fans it really helps to keep air moving over the GPU's.
Results may vary, as can be seen from the videos, I am not running the 2x factory front 140mm fans, I have changed them out for 3x Noiseblocker Bionic E-Loop B12-P's (PWM) that in concert have doubled the CFM coming into the case and extend the airflow path lower than that of the 2x 140mm fan's. That out of the way, I believe that this mod will still yield positive results with the factory case fans. I used a Corsair AF140 fan for the mod.
Please use protective eye-wear while performing the mod and take great care to clean the metal shavings that will be a result of drilling into your case. Be sure to use a fabric cloth to collect said shavings or a min-vac. Please take care to wash your hands after the mod as the last thing you want is to touch your eyes with undetected shavings on your hands!
A good fan 120mm comparison:
(Oh and a correction, I state that I am using B14-P's in the video, there is no such thing, I am using B12-P's)
Noiseblocker B12 vs. Noctua NF-P12
Default GPU clocks:
+100 core/+300 memory (1254 MHz boost) default voltage/vbios:
CPU: i7 4930 @ 4.6GHz with 1.398V as measured by DMM
GPU: 2x EVGA 780 Ti SC w/ ACX Cooler
Case: Corsair Air 540
Motherboard: Asus Rampage IV Black Edition
Cooling: Phanteks PH-TC14PE, 3x Noiseblocker Bionic E-Loop B-12 P's
PSU: Corsair RM 850
Memory: 4 x 8G Corsair Vengeance Pro 2133 Mhz with Akasa Copper heat-spreaders. RAM Disk!
Storage: 2x 500G 7500 RPM HDD's and one 258G SSD
OS: Win7 Pro
Total cost: ~$3k (not counting the monitor, keyboard, mouse and Astro A50's which I already owned, just everything above.)
Part 1: https://www.youtube.com/watch?v=X96M8weNpvg
Part 2: https://www.youtube.com/watch?v=X190b9dvZG8
Part 3: https://www.youtube.com/watch?v=XGtlksj-Fdc