I've run all kinds of games on my computer and never had these issues, I even completed the full bg3 beta when it first came out. Lately it's been dropping frames, not loading certain parts of characters, not showing models correctly, all on the lowest graphics. The worst thing is that when I click anything it takes 3 seconds to respond and then everything happens at 50% speed. I ran the game at high graphics just a year ago and had almost no issues. I have 16gb, an i7, and I ran other more demanding games perfectly fine. I tried reinstalling and I'm not sure what else to do.
I've had similar issues and I did a bunch of searches and finally ended up dropping my graphics settings much lower than I had to even a year ago, and I also did the following three things: 1) delete everything in C:/Documents/Larian Studios/Baldur's Gate 3/,
except for PlayerProfiles., 2) Find the bg3.exe file, which is somewhere in the install folder, I can't remember where off the top of my head, right click on it and under properties change it to run in Administrator mode, 3) also under Properties > Compatibility > Change high DPI settings > Select ‘Application’ for “Override High DPI Scaling performed” under the ‘High DPI Scaling override.’ When I did those three things, it gave me enough of a performance boost that the game is once again playable. I still have issues at times. One of the biggest is ranged spells having a two to three second delay in animation after firing, and occasional texture drops. I know how frustrating it can be, so I sincerely hope trying these things helps you as it did me.
