EXS 24 Logic Sampler Users Group

I create a song with say drums, bass, keys. All using exs instruments. The
first one plays alright, but the following instances don't respond straight
away. IOW I press play and the first few notes of the bass and keys don't
sound. With audio I realise that reading from a hard disk can't happen
instantly and stopping the sequencer for a second seems to let Logic get
ready for instant playback. But the exs is a sampler and loads into RAM. But
it seems doesn't behave like a hardware sampler.

I think I saw this mentioned in a thread regarding playing multiple exs's
and/or touch tracks of multiple exs's.
What's the story?