How to prevent gnus from always downloading full index

[Andreas Hilboll]

Hello,

I'd like to start using GNUs to read mailing lists via nntp/Gmane. Works
fine so far, but each time I press RET on a group name in the *Group*
buffer, GNUs seems to download a lot of data (in case of the org-mode
list, some 30+M, which takes 10+ seconds).

Maybe I don't understand the workings of NNTP and GNUs properly, but
shouldn't it be possible to somehow cache these data locally? Waiting
many seconds for entering a group seems to be a waste of time,
especially since at this point, GNUs already knows the number of unread
messages (as it's being displayed in the *Group* buffer) ...

Any help is greatly appreciated!
  Andreas.