I am a bit concern regarding this issue and maybe i can be wrong. My both GPUs seem to be working fine but the GPU usage makes me a bit worry. The problem is that my GPU 1 is getting 94% of usage while GPU 2 is getting 97% however both are overclocked to 1500mhz and 7710mhz memory clock and the power target is 116%. here is the screenshot in game of GPU usage. I have tired to switch gpus and instead GPU1 gets 97% of usage while GPU2 gets 94% of usage.
Id don't see any problems. Usage is fine, if the difference between them would be greater, then i'd say you should worry.
The usage is fine. You may have a small bottleneck but your getting over 100fps so I would not worry about it.
I had 980 SLI before. I discovered that my 3770K bottlenecks them. Especially in cpu(along gpu) intensive games (BF4 for example) don't link me please to benchmarks. That's my experience with it.