Dear I own two cards, gtx 690 and gtx 780. on another thread (http://www.tomshardware.com/answers/id-3329068/geforce-gtx-690-render-quality-poor-gigabyte-gtx-780.html) i'm also trying to find out any reason. if buying a used 690 was a good decision or not.. I bought 690 while I already have 780. I created one scene in 3ds max 2017, set IRay it's renderer, and started target rendering output for 3 minutes and 4k of resolution.
the 780 one, finished in 4.3 minutes.. while 690 finished in 5.2, also output quality was not so good as compare to 780, then i posted that thread..
After reading comments of some gurus, I realized may be some settings should be changed, like turning off sli was a good idea but I didn't turned off.
For Blender, I 've seen many videos in youtube, they run one 690 (disabling sli and using only one GPU) 690 runs like a charm but i am unable so far to achieve that performance or setup the Hardware configurations ..
I don't know why Autodesk (the giant in 3d applications) Certifies and recommends only 4 GTXs along with Quadros.. GTX 690,Titan, Titanx, and TitanZ ..
Check out this link if you doubt.
https://knowledge.autodesk.com/sites/default/files/file_downloads/3dsmax2017_GFX_Results.pdf
Page 3 for gtx 690 and page 6 for 780, and my 780 is under "tested" ... not certified. while i'm seeing better performance in 780 than 690.
It purely seems 690 is for 3D Applications/Rendering not for Gamers..
I'm more than 100% sure there must be some settings issue, some configurations or there must be something that Autodesk recommends this 690. You know 690 is 2 generations OLDER but still recommended by 3D Giant Autodesk, so that is not without any reason.... even in 3ds max 2015, 2016, 2017!