Same issue here, when i disable Perfomance overlay typing in the game console i get around 150fps but immediately drops to 15-20 on respawn. Got it to work better yesterday, getting 60-70fps by updating the drivers to latest nvidia just released and i was happy i finally sorted it, played for a good few hours but today it went back to 15-20fps. Anyway those frames were still low as disabling perfoverlay temporarilly gets me 150-170fps which makes more sense. I spent hours trying to find a permanent solution online, but there isn't much and none of the options mentioned seem to work. Even clean re-installed the drivers, switched to the more stable RTX studio drivers, nothing. Pitty but such an old game won't be getting any fixes now.
