I often used to get frustrated with the speed of eclipse on my machine. Then I heard from my friend how I can increase the initial memory allocated to Eclipse. U just have to pass values from the command prompt using the vmargs argument.
eclipse -vmargs -Xms256m -Xmx256m
This single change, gave me a very good "perceived" performance benifit while using the IDE.
Other tips to increase the performance of Eclipse can be found at: