Surface book base GPU issue - slow

I have the surface book 3. When the tablet (CPU is detached from the base  keyboard (GPU), it turns on and runs super fast with no issues.

However when the Tablet CPU is connected to the keyboard base (GPU), it takes a long time to start up, when you connect an external hard drive vis USB it takes a good while to register in explorer that its been connected, when you press shut down it does not shut down (only when the tablet is disconnected from the keyboard base. 

Any suggestions?

Thanks