For anyone, perhaps Jesse mostly:
I have RT3 running on a PIII 450 with 320mb RAM, 512mb swap.
On the same machine runs mysql 4.0.14 - i used my-large.cnf for my.cnf file.
I applied this two indexes when I was still on RT version 3.0.4:
create index group1 on CachedGroupMembers (GroupId);
create index member1 on CachedGroupMembers (MemberId);
which improved RT’s speed by some %.
I upgraded to 3.0.5pre3 yesterday and have positive feedback regarding speed
(haven’t checked changelog).
Clicking on Comment, Resolve, etc… has now got the same speed as RT2,
whole RT3 is just a bit slower (in %, about 5% to max. 8%, which is normal
because of mysql 4.x).