It most definitely isn't CPU bottleneck for various reasons:
1. The performance with GTX 970 was way better than now with the GTX 1070ti
2. The 20% bottleneck on your screenshot is considering a original 2600k at 3.4ghz, my 2600k is at 4.6ghz, the calculator you used allows maximum 4.4ghz (130% CPU clock) and even then the bottleneck percentage lowers to 9%:
I would say that at 4.6ghz the bottleneck could be around 7~8%, that sure wouldn't cause the GPU use less than 20% of it's power
Specht77 got a reaction from Origami Cactus in GTA V - Terrible performance after GPU upgrade (Low GPU Usage)
