If you import from the whole 'Processed' folder at once the import speeds will drop the longer the import goes on. Importing in smaller batches will overcome this however this will still take time if you have alot of hands. You can start with the most recent ones and work backwards from there since those would be most relevant however please note that:
1. I don't know if reimporting will be quicker than restoring from a backup file.
2. If you do not have all of your original hands in your current database in the 'Processed' folder then those can be exported from the original database:
Guide: Exporting Hands3. If you have a large quantity of manually edited tournament results then you will not get those reimporting from the original hands again so you would either need to restore from a backup file or exp[ort the tournaments from the original database which will create summary files with the edited results.
4. If you reimport and want to transfer notes you can do so via 'Database -> Notes'.
5. Marked/tagged hands can only be transferred using backup & restore.