It’s GPU memory, not RAM
In windows you can take a look at your GPU memory usage by going to the Task Manager and going to the Performance tab, then there’s a listing for the GPU where it’ll show how much GPU memory is in use. If you run out the game will crash.
Perhaps, but I’m not convinced this is the case. 99.9% of players never experience this issue, even if they have very low-end GPU’s. And the few players that do experience the issue seem to experience it regularly, and often have high-end GPU’s.
The bug might not be an indicator that you’re out of GPU memory (though it should be, since that’s what it’s saying) But, that doesn’t mean that changing the virtual memory will fix it since that does nothing for the GPU.
The only thing I can guess is that since UDK is so old it may not be able to properly work with newer cards. I’ve seen some games before say that my GPU has less memory than it actually has.