if you used an app, undo it, uninstall the app, remove it from the SystemPreferences->Users&Groups->LoginItems, then restart (there will remain leftovers). when you have used the trimforce command, use the trimforce disable command to undo it, then restart. Do not use Trim: it can cause timing issues in the Disk Controller - the Garbage Collection.
Ogelthorpe is right: the 850 has a mixed reputation, for whatever it is worth, but this has mainly to do with the slow write problem and the trim command vulnerability It is better not to have other partitions on it. Then I have the following comments to make:
If not redo it on the destination mac machine, either inside (from the Recovery Partition) or outside. Check if the 850 is correctly formatted: Partition Table GUID, Mac OS X Extended (journaled).
