how is the cpu and gpu utilization when you play? if the cpu is at 90-100, what about the gpu?
in any case, you have an unlocked cpu, so even if it bottlenecks the sli, you can just oc the cpu
i have tried to overclock the cpu. but i still get the high percentage. especially in BF4 and assasins creed unity. when i reach the 100 % i get some annoying stuttering. im kinda new with the SLI setup.
The processor should be running at 99% anyway, that is the "optimal" usage (In theory). You are getting the most out of the CPU without maxing it.
That being said, bottlenecks occur when the CPU is at max, and the cards are not.
100% CPU and 40-50% GPU is a bottleneck.
What is your display resolution? Low display resolution puts more load on the CPU. High display resolution places more processing load on the GPU and is preferable.