Trying 2.0.0-beta4 I suspect an issue with Memcache
Loading Admin UI with Memcached is way way slower than Redis or just filesystem.
It is easily testable with Launchpad. Here is some screenshot.
To switch from one to another I just changed the ENV vars.
As Symfony Cache seems to be used, the only reason would be that now,
data stored in the Cache are bigger and Memcache does not really like that.
Look the difference Memcache on the right, Redis on the left
Also I have done a Backfire profile:
=> getMulti of Memcached is slow that is the issue.