Heavy stuttering and extremely low FPS on 64-bit exe (PC is 64-bit Windows 10 OS)

[Frost Thicc Yo]

My google-fu seems to be weak or maybe there isn't anyone who has reported this exact issue. So, I am able to run this game reasonably well at about 40 to 60 fps when I use the 32-bit application to start it. However, when I run Project Zomboid using the 64-bit application I get good FPS until I actually load into a singleplayer or multiplayer game. At that point, I start to get heavy stuttering, input lag, and low FPS (probably in the low 20s at max zoom in, and under 10 when zoomed out at all). This occurs whether I have mods enabled/loaded or no mods enabled/loaded.

I have tried changing "-XX: +UseZGC" to "-XX: +UseG1GC" with the result being slightly better FPS at most (about 2 to 4 FPS more). Additionally, I have tried changing the -Xms and -Xmx lines in both the batch file (then running the batch file) and json (then running the 64-bit exe instead) to increase the initial and maximum allocated RAM with no noticeable result. I have tried some other things like changing resolution; running in windowed, bordered fullscreen, and fullscreen; updating my Java and ensuring I have 64-bit Java installed; updating my graphics drivers; running in Windows game mode; and so on with no noticeable results. I even tried putting an exclusion on my Zomboid folder in the Users directory, as well as the Project Zomboid folder in steamapps\common. At this point, I am not sure what else to try so any help would be greatly appreciated whether from a Dev or not!

P.S: The reason I'm trying to run the game in 64-bit is to allow for more RAM to be allocated to the game, since 32-bit Project Zomboid doesn't allow more than 1200 MB in the batch file or json file.

Below are my relevant specs:
8-core Intel Xeon Silver 4215R @ 3.20Ghz
30GB DDR4 RAM
4GB Nvidia Quadro RTX 5000

[Beard]

Best I can guess is that the Quadro card drivers are just not good enough for this specific game and OpenGL, likely the 32 bit drivers have better support / performance which is why they can run the game well but not the 64 bit drivers. Overall the Quadro card is not really made for gaming.

[Frost Thicc Yo]

Ah, alright that must be the case then. Thank you for the answer!!