I think there is a lot to learn from it still, even if you're highly unlikely to be writing the same kind of graphics code.
The book has a great balance between: - Micro-optimization - fiddling with ASM and data structures, memory alignment and such, custom math functions that lose precision in tradeoff for great acceleration due to hardware features
- Algorithmic optimization - trying to do things in ways that are mathematically faster (computational complexity)
I work in enterprise software, not games or anything touching hardware.. it is depressing algorithmic complexity is ignored so often these days and if you give an interview question it is often greeted with blank stares and there seem to be college undergrad curriculums which don't even touch on it.
I'm in that camp that feels like software has gotten so inefficient in a lot of cases that the user experience is no faster than 20 years ago. We have acceleration & optimization for certain things but every day applications are no faster than they ever were and when you have to use a web application stuff is often a lot slower than a native app was 10-20 years ago.
There are still a lot of great college texts on computational complexity even though trade publications ignore this stuff with a vengeance.