Dark Souls 3 GTS 450 768p gameplay

Dark Souls III gameplay and performance test on 6 years old Ge Force GTS 450 card,at custom settings 1366x768p. Game is poor optimized and working very strange. I had notice that i even lose 4-5fps sometimes for some unknown reason even when i change graphic options and resolution,and revert options like before hmmm very strange game. Game is using 99 percent of gpu core and 1000 mb vram checked in MSI Afterburner. I am playing game on Windows 7 Ultimate x64 sp 1


PC Specs

i5 760 3.3 GHz Turbo Boost On
4 GB DDR3 1333 MHz stock
Palit Ge Force GTS 450 1GB DDR5 930 MHz oc
ASRock H55M-LE motherboard
WD Caviar Blue 1 TB
CoolerMaster GX 750W PSU
Benq GL2460 24 inch 1920X1080p