mathaetaes: Again, it depends on your AV... but it's not the CPU usage of the AV that's the problem, it's the detection technique.
It's pretty common these days for malware to remain encrypted on disk, and only decrypt in-memory when run. This means you can scan a file on disk with AV and it won't hit any of the signatures (encrypted data is effectively just random bytes).
To get around this limitation, AV engines have started hooking the operating system and detecting when executables or dlls are loaded. They monitor the thread for a bit, scanning for malware signatures, and after some period of time (on the scale of minutes) they detach and the program runs normally. In some cases, they even go so far as suspending the thread while they're scanning, since detecting a virus after it's running is far less useful to the user than detecting it before it can run.
The problem is that while they're attached and monitoring, threads can be suspended or run slowly. We're loading 1.5 gb of data into memory just to get to the menu... that's a big chunk of data to scan for malware, and it could be slowing or suspending the loading processes as it's scanning.
It's a bad idea from a security perspective, but most AV's have some notion of a whitelist or trusted files directory... files or executables in that directory are ignored (not scanned). If there's a chance it's your AV, one test would be to exclude the BG3 directory from being monitored. You might also have to turn off real-time protection or memory protection or whatever your specific product calls it - the feature that scans new processes in-memory. If doing that speeds things up, you at least know the problem.... though I strongly advise against leaving your system in that state.
At any rate, it's a test you could do now, before you spend money on more RAM.
All that said - if you're getting BSODs, that's typically a driver or hardware issue. Failing RAM chips or hard drives could cause this, as well as buggy or corrupted drivers. If you're running the latest drivers for all your hardware, that rules out drivers (or at least rules out anything you can do about them), which leaves hardware. My guess is your BIOS has a memory test you could run to diagnose errors in RAM. You could also probably run a disk check against your drives to check for bad blocks. rrors elsewhere might need to be A/B tested (swap the component with a known or assumed good one, put the system under heavy load, see if it crashes. Much easier if your BSODs are reproducible rather than random).
The last time I had video card hardware-related issues, it manifested as a hard reset, not a BSOD... so hopefully the fact that you're getting a BSOD means some of your hardware is still intact. If you take a picture of your next BSOD, it should have an error code you can try googling for to get some indication of what happened, which may also lead you to in the right direction.
Sorry you're dealing with this... computer issues suck. I'm curious what you find out, though. Please keep us updated. :)
Unfortunately the AV stuff didn't work. I'll try testing my drives. This was very informative, thank you.