Méven Car has written a pair of interesting blog posts (part 1, part 2). The first post is largely about some of the recent new features and performance work that have gone into the Dolphin file manager 26.08 release, as well as the KIO framework. The second looks at the performance improvements and benchmarks for previous, current, and upcoming releases. Copying many small files is more than twice as fast as it was in April. The gain falls off as files get larger, which is what you would expect: the fix is to the per-file overhead, and once each file carries a megabyte of actual I/O the overhead stops being what you are waiting for. There is still a gap with cp, discussed at length in the July post. KIO is doing more than cp does, but not five times more, and the batching work that closes most of the rest of that gap is still in progress.