Description
The *.4 Symfony versions are always the slowest in a branch (e.g. 4.4 is the slowest 4.* version) because of all the deprecated features.

For the same reason, the *.0 versions are usually the fastest Symfony versions. However, for 5.0 this didn't happen. See phpbenchmarks.com results:

Maybe we could do some Blackfire profiling to find possible ways of improving Symfony 5.0 performance. Thanks!