Rational Application Developer Performance Tips
While doing some Websphere work one thing I do notice is that the Eclipse based IDE is a resource hog with quite a bit of background services and publishing going on (though ultimately to help the user in the long run).
Luckily there is a document from IBM on performance tuning the beast.
https://www.ibm.com/developerworks/wikis/download/attachments/113606723/radtipsv754.pdf