Ok, if you do not need maps and 3.4 is not updating, check this thread → Tutorial: Sync 3.4 NON-NAV APIM: Failure to Update to Newer Version Sync 3.4
For NA non-NAV, 16 GB APIM should be enough. The previous link will tell you how to free up some space to perform the upgrade. After that, you may or may not be able to install all packages again.