Ninja Gaiden Sigma [NPUB30851]

Tested on: RPCS3 v0.0.5-6633 (b0352d6) Alpha [2018-04-02]_win64

Played for 1hour, the game is perfectly playable, graphics renders perfectly and sounds too, just some little FPS drops in some areas.

With PC Specs: i7-7700HQ @2.8ghz, GTX 1050 GDDR5 4GB, RAM 8GB DDR4

With the configuration:
CPU
PPU LLVM Recompiler
SPU ASMJIT Recompiler
SPU Threads Auto (it's faster than 1 to me)
Liblv2 only, thread scheduler + loop detection

GPU
Vulkan
Res. 1280x720 Scale 4K
Threshold 16x16, GPU Texture Scaling

it is very slow on my pc. why?
i7-6800k @3.4ghz; GTX 1070
the setting is the same.