I recently purchased and installed a 970 SSC with the new ACX 2.0 cooler. Before purchasing I read that the temps were usually pretty cool, and that they usually stay around 60c under load. However, I have found that when playing a game like The Witcher 3, my GPU reaches 75c after about 5 minutes. I'm not sure if this is normal or if it is something to worry about. My case is the Cooler Master 430 Elite, and i'm running it with 3 case fans, and one of them is a side fan blowing directly on the card. I bought a new case (NZXT source 530) and some extra fans that I will be switching to in the future. Are these temps fine, and possibly just due to my case and airflow, or should I return the GPU for a replacement? I cant imagine it is my case because I use to have a ZOTAC AMP 670 and I never saw the temp go over 67c. Also, my CPU temps are fine never really getting much higher than 60 or 65c under load.

Do you have a custom fan curve on your new 970 ssc ? The built in curve on the first bios is not aggressive and favors less fan speed for lower noise. I have 2 of these cards and they do the same thing. 75 degrees is not anything to worry about under load. It seems also that these ssc cards use higher voltages to reach the advertised boost clock they are factory set with, thus higher heat output compared to a normal 970. You can use a custom fan curve if you want to get it lower or use that bios switch to go to bios 2 (while the system is fully powered down) and it uses a more aggressive fan curve and lets you set a higher power target. Or you can your a software fan curve in after burner or precision X. Though anything under 79 degrees on these card is safe imo.

Okay, so, I have gotten all the parts and installed them with good cable management and airflow in the NZXT Source 530. I have even gone as far as removing some of the HDD slots to clear the airflow path for the two front fans. I Installed 7 fans in total. 1 in the back, 2 on top, 1 on the bottom, 2 up front, and one on the hinge in front of my GPU. The top and back fans are blowing out while the bottom and front are blowing in along with the one on the hinge blowing air onto my GPU. The highest temp I have seen now was 72c. That is slightly better, but I expected to see lower temps than that after installing all of those fans and the new case. 

I assume the 72 degrees is with the card default fan curve ? If so that is very good depending on what your ambient temps are. If it is the default fan curve, it will favor low noise over fan speed. 

Running a custom fan curve will help your temps out a lot.