Low GPU usage even without PhysX

[Kirizaki]

I played it back in 2013 or so, but yesterday I decided to install it, cause I've been playing Arkham Knight and wanted to see how this jewel runs on my current rig, cause back then I so wanted PhysX but the performance was really awful to have it enabled. And it is still awful... the most annoying part was to see the benchmark drop to 20~30fps at the penguin part, which is the most PhysX intense, and both the GPU and CPU usage arround 40% (I disabled the 62fps cap). Tested all sorts of things I found in the forums, reinstalled nvidia drivers, installed old PhysX drivers, and nothing. As I know PhysX isn't suposed to run on a single card, I tried disabling it, and now fps averages at 100, playble, but the usage is still low, sometimes going above 80%. sometimes dropping to 20%. It's weird that AK, a much newer game runs at higher fps at ultra than an old game.

I was almost giving up, thinking "hey, maybe the game is just poorly optimized to new architectures" until I found this video:

https://www.youtube.com/watch?v=racorgMKXUo

The same GTX 1060 as mine and he gets above 90% usage, a much higher fps, even with PhysX on, the penguin part drops to 40~50fps, which I could totally live with. WHAT DID HE DO?? Anyone have any idea?

Specs:
FX-83020E
GTX 1060 6Gb
1x8 Gb RAM DDR3 1600Mhz

[Sazzouu]

The difference is the CPU
Since the CPU tells the GPU to do something if you CPU is not fast enough to handle the workload your GPU will never be pushed to it's limits.
Try switching the Anti-Aliasing mode to MSAA instead of FXAA since the first one punches the GPU while the second one goes for the CPU.

You could also play around with the DirectX settings. With your GPU you can put them as high as possible. I mean I did so with a GTX1050ti and I basically have around 100FPS.
Also activate DX11 Tesselation. This will also take away some CPU load for you (not recommended on Extreme Details tho).

EDIT:
Maybe look for the Nvidia Control Panel and check if your GPU is selected as the PhysX-GPU, not the CPU. This was one big problem when I tried PhysX the first time

[Kirizaki]

Well, in fact, I'm planning to update my kit and get a newer CPU, since it started to bottleneck a few new games. But as I said, the CPU workload is also about 50%, so the problem is not a bottleneck. I've seen cases where a game, especially dx9 games, pushes just one core to it's limits and leaves the others idle, that's also not the case (i've just run a test to check the per core performance), all the 8 cores are half used. This CPU actually does a good job with most games, this one shouldn't be a problem.

And yes, i did select GPU as the PhysX processor on nvidia control panel.

EDIT: Just to have it stated, there isn't a single resource on my system that is being fully used.