This will not be specifically used in Pale Moon, for a few reasons:
- The most important one: the compiler used doesn't include support for compiling with these SIMD extensions (in fact, SSE2 support is already half-broken; go Microsoft! ). This would mean that if it were desired, it would have to be manually programmed in assembly for every single function where it would be desired.
- The specific advantages of using SSE3 and SSE4 would be mostly interesting for video and sound processing, not for a browser. The areas where these kinds of calculations are used (graphics libraries) are already manually optimized.
- Every higher SSE level further limits the amount of computers the browser will run on. Pale Moon aims to be a middle road, to cut away support for archaic architectures, but still allow a fairly broad user base.
- Using a different compiler that supports more advanced SIMD instruction sets (Like Intel's) would potentially be an option, but compiling with a different compiler on Windows is not properly supported in the Firefox code base, and has shown to lead to either build errors or totally unstable binaries.