But I don't think that it has _anything_ to do with the individual programmers inherently understanding performance better. There is likely a huge organization

But I don't think that it has _anything_ to do with the individual programmers inherently understanding performance better. There is likely a huge organizational focus on performance and more people expressly dedicated to the task because it is a higher priority for Epic. It is directly correlated to Epic's ability to deliver a successful product to game companies, whereas for browsers it is slightly more orthogonal to their success. LLVM has a bunch of contributors who likely understand the intricacies of machine code better than either of us, and: > Each LLVM release is a few percent slower than the last. > The larger problem is that LLVM simply does not track compile-time regressions. While LNT tracks run-time performance over time, the same is not being done for compile-time or memory usage. The end result is that patches introduce unintentional compile-time regressions that go unnoticed, and can no longer be easily identified by the time the next release rolls out. https://nikic.github.io/2020/05/10/Make-LLVM-fast-again.html https://nikic.github.io/2020/05/10/Make-LLVM-fast-again.html