One Click Lag Fix, does this all for you. Simple download it (available in market as well). Install it and run Root device recovery 2e. That’s what we used to unroot our device at wowtechy!. All the rest will be done by the app it self. Just in case you press home or back button while the process is running, go back to the app (OCLF) and you should be fine.
Once all is done, you will see an addition of Superuser Permission in your apps. To test your root, download any network app, or apps like PicMe and see it work. It will ask you for Superuser Permission everytime you’re about to run a rooted app, which can be set as default.
Enjoy your rooted Galaxy S device. The lag should have been fixed for now, if gaining any problem check XDA
Note: We successfully tested this on our device which is still in use. We hold no responsibility if for some reason your device gets bricked. (it shouldn’t though). For basic Android dummies, we`d recommend running the simple root recovery command and the lag fix. Un-root can be done easily as well via the same panel. Playing around with the app with not much knowledge about kernels etc might brick your device.