GNU Sed 4.3 now has regular expression matching that is around ten times faster than previous versions. Also improving the performance in sed 4.3 is unlocked I/O. With the unlocked I/O, the I/O operations are now generally faster too.
Sed 4.3 also has a range of other fixes and minor improvements. More details on this first GNU project release of 2017 can be found via the release announcement and project site.