Hi,
I did the following tests:
perform a clean via Project --> Clean.
Under Eclipse Juno with latest updates and the latest development release of JBoss Tool for Juno:
(a) clean: 5 sec
(b) CDI Builder: 55 sec
(c) compile: 1 min 5 sec
(d) JBoss KnowledgeBaseBuilder: 1 min 20 sec
(e) CDI Builder (again): 16 min 30 sec
(f) compile (again): 20 sec
total time: 20 min 15 sec
Under latest JBoss DevStudio 6.0.0 Alpha 2
(a) clean: 15 sec
(b) copy resources: 1 min 35 sec
(c) compile: 45 sec
(d) CDI Builder: 10 sec
total time: 2 min 45 sec
The validators are not relevant for this project because the project doesn't use CDI nor EL as I already mentioned.
I realized that the eclipse version of JBoss Tools is using a lot more RAM or at least releases the RAM not so frequently.
HTH