mathaetaes: ooh, 30s is quite a lot. I wouldn't even cause that latency... that's a lag. Yeah, not seeing that here. My system is home-built and ever-evolving, but the CPU is probably 5 more years old.
Do you happen to have the game on a spinning disk or something? My gut makes me think it's probably related to redrawing the level-up scene, which probably means loading a bunch of new elements into memory from disk (at least the first time it happens).
Since the characters level up pretty close to each other, do you see the lag between each character if you level multiple at once, or only when switching from the game to the level-up scene?
I wonder if your GPU is just purging the game assets from memory to make space for the level-up scene or something. Depending on the rest of your setup, paging can be a serious drag on performance. It's hugely noticeable if you're reading from a spinning disk; less so from a SATA6 SSD.
Do you lag when changing areas as well (e.g., act 1 outlands -> underdark? )
My game and saves are on a 2T SSD, so no spinning platters....
I do not see the same lag when changing areas, or I should say the load times are similar to Pre-patch 8