Strange black on textures

I’m not sure what the cause is.

I know that previously, on very high quality models, I’d get black faces on some maps. Although lately, it seems that not all of them do that. This means that the lighting is involved, and I can’t really do anything about it.

However, now it’s extended to standard HL2 and CSS models, with massive black patches all over vanilla models. I can’t figure out why, nor can I find a fix.

It’s only recently started happening, so I think something happened, either with the updates, or with my computer.