You can switch off the plug-in by going to Window -> Preferences -> General -> Editors -> Text Editors -> Spelling, and unchecking the box title 'Enable spell checking'.
Disable necessary startup plugins Windows > Preferences > General > Startup and Shutdown
Uninstall not necessary plugins
To view Eclipse Memory usage enable this option
General -> Show heap status
To limit memory usage by file eclipse.ini
-vmargs
-Xms128m
-Xmx1024m
-XX:MaxPermSize=128m