Samsung has released a new version of Magician. Changelog and download link are below. http://www.guru3d.com/files-details/download-samsung-magician-4-5.html
i've been using over provisioning since last night and it seems to give the system extra stability, little to no crashes in fc4 now.
I'd be surprised if the cause of your crashes was anything to do with over provisioning amount. Most likely stability issues with stock or overclock on your CPU/GPU/RAM. (You should be getting zero crashes, not just little to few crashes.) I updated my firmware for 840 EVO, no issues so far. My drive was performing fine just prior to update anyway, due to a recent refresh I had done.
