Performance drops in certain bossfight

[kretelos]

Hello, first of all thank you for this fix, I have clocked in over 100 hrs on my old GTX 770 2gb, game runs fine most of the time at 1080p lowest locked 30 fps. But there are minor issues, performance drops when changing locations sometimes (needs to do a quitout and it goes back to normal), and when looking in certain directions in some areas (also can be somehow fixed by doing a quitout). But during the Dragonlord Placidusax bossfight my fps is 10-15 when I look at the boss and there is no change even if I set the resolution to lowest possible. Did someone else also face this problem? I don't know much about this stuff but I suppose this might be a vram related issue?

The rest of my system: i7-4770, 16gb ddr3(4x4gb) 1600MHz, game runs off a sata ssd.