fans effect on gpu cooling

[Cyracus]

I recently built a new system and one of my requirements was a side intake to feed air straight to the gpu, thinking it would improve cooling quite a bit, and have also mentioned it as advice, and now I have test results ready to share. My system is an Asus Z170-a mobo, Gigabyte r9 280x windforce OC, and i5 6600k in a Phanteks Enthoo pro case, front intake and top exhaust are bitfenix 200mm spectre pros, side intake and rear exhaust are Phanteks F140XPs running neutral pressure. Monitored temps with HWmonitor and in Furmark which I used to stress the GPU 1920X1080 8XMSAA, Dynamic background, burn-in, xtreme burn-in, post-fx. Tests in order of how I ran them, ambient temperature was within 1ºC from the first test to the last, fan control with Asus fan xpert 3.

 

80ºC no fans
74ºC fans silent
71ºC side fan max rest silent
72ºC side+rear max
74ºC front+top max

71ºC all fans max

 

Originally just set out to do the first 2, then realized I could get a better picture, and then decided to make this post. So Shutting down the fans to use as a baseline just having fans moving air dropped gpu temps 7.5%, and ramping up that side intake improved on that 4%, or just over 11% total, side fan and rear max provided a nice neat 10% reduction, front and top max performed equal to the fans running regularly, and running all fans maxed returned no further improvement. It's not as much of an improvement as I guessed, but still an improvement.

[Moonzy]

though i'd prolly keep the fans off during idle

and only spin silently when under load 

[Cyracus]

That's actually how I have it setup sadly my attempts so far to link side intake speed to gpu temp have all failed

[FourCorners]

Were the GPU's fan spinning normally during all the testing too? Or were they off when testing "no fans"?

[Cyracus]

yeah, I left the gpu fans alone, can't afford to end up breaking it. They hit 100% at 80ºC and if I recall correct 70% at 71ºC and 75-80% at 74ºC didn't even think about noting them until I'd started writing the post