I had a issue which is a commonly raised question regarding Android Eclipse in stackoverflow.
Eclipse is taking too much time to build the workspace. This started after I tried to update both ADT bundle and SDK. I followed many steps to solve this, which I've gone through the stackoverflow
i.e:
1.Uncheck the Build Automatically from Project Tab
2.Window - > Preferences - > Android -> Build -> Skip packaging and dexing export or launch.(Speeds up automatic builds on file save) etc etc....
But the issue is still there.
System Config: RAM - 4GB & Win 7(OS)
You can also try all of the following to speed up your current IDE (apart from buying a SSD):
--clean
optionI noticed a notable performance degradation using Eclipse to develop Android apps since when I started, at SDK 7. I warmly suggest you to switch to Android studio, as it is now The official Android IDE. Migration is almost straightforward and you'll get many advantages, native Android wear support and a much more effective and integrated dev environment.
Gradle, the new build tool used by default, builds the workspace incrementally, only re-compiling units and modules as needed. I guess it's up to 30% faster than Eclipse in building it up.
This answer is counter-biased since I'm a fan of Eclipse