Sync 3 is extremely lagging after updating to sync 3.0.23219, but is fine whe I have the instalation USB inserted.

Try a master reset, but as far as remember, there’s an incompatibility with old map versions and latest Sync3 3.0 builds…

I will look up some guide and report back.

Here it is Sync 3.0.20204/23219 with EU 2.21 (F11) or EU 2.22 (F12) or EU 2.23 (F13)/EU 2.24 (F14) Map Installation

Install the latest maps available as per that guide, you can stay at the latest 3.0 build you already have. Once the maps are updated, it should be fine.