Hey guys, I've been having this problem since enabling sli. My cards work fine in benchmarks, but when playing games they max out at 70%. A few weeks ago I shuffled the cards around in different slots and it seemed to reset something and for two weeks they worked at 95+% like they should. This morning I had a display driver crash and now the problem has came back. I did a custom fresh install of all graphics drivers which did not help. My cards work fine by themselves, and I am not bottlenecked by anything else in my rig. Any ideas?

You didn't read my post in its entirety. They were pegging both cards for over 95% usage for like two weeks until the display driver crash. Here is everything you need to know.
 
My specs:
Mobo: EVGA Z87 Classified
CPU: I7-4770 
RAM: 8 GB GSkill Sniper
GPU: SLI GTX 970 FTW+
PSU: EVGA Supernova 750 G2 (gold)
SSD: Crucial MX100 256GB
 
So I'm going to be a little bit more detailed since my OP was off my tablet  before I fell asleep.
 
1. The initial problem was apparent as soon as I built my rig a few months ago. The problem is low GPU Usage (~70% in both cards), and a FPS of about 40.
 
 
 
2. I initially contacted EVGA tech support and they had me do all the basic troubleshooting steps which I had already done. I did a custom fresh install on drivers, went through all the settings, checked game settings, etc. One of the techs suggested I was CPU bottlenecked which is not the case with an I7-4770. My CPU core usage never exceeds 40% in any core while gaming (this was checked with MSI Afterburner). I also updated mobo BIOS and all associated mobo drivers offered from EVGA.
 
3. One of the more helpful techs suggested I try a different PCI slot. I initially had my cards in slot 1 and 4 (suggest placement). There are five slots on my board and slots 1, 2, and 4 are PCI-E x16/x8. Slot 3 and 5 are PCI-E x8. I moved my card from slot 4 to slot 2 (side-by-side), and the problem was resolved. My GPU usage went to full potential (95%+ and my FPS went to a solid 60). I then ran into heat issues with one of the cards over 80 degrees C because of the lack of air flow. I decided to try slot 1 and 3 which did not work (low GPU utilization). I then tried the original slot (slot 4), and low and behold it worked!
 
4. During benchmarks (firestrike, Valley, etc), the cards work as advertised with full GPU utilization. Only during gaming (GTAV, Witcher III) that I'm seeing this issue. I haven't played anything else (that puts that type of pressure on my cards) because I frankly don't have the time. Both games show the same symptoms, GPU utilization capped at 70% and poor FPS.
 
5. The cards worked for 3-4 weeks as advertised in both GTAV and Witcher III and I had no FPS or low utilization problems. I was a happy gamer until yesterday morning. Yesterday morning I experienced a series of display driver crashes, and my GPU utilization now is capped back at ~70% and low FPS.
 
EVGA tech stated this is a performance issue anomaly. What does that mean? Does anyone have any suggestions on what I can try? If you need any other info, let me know. I'm on the verge on jumping ship, for I dropped a lot of money on this rig with nothing but headaches.
 
 

1080p. Tried rolling back drivers - didn't work. Tried swapping processors to an I5-4670, and that made the issue WORSE. Looks like possible issue with my mobo. RMAing the mobo since my cards work 4.0.