Inter-App Audio CPU Load Issue

I just purchased Cubasis 1.9.9 to sequence my Arturia iMini and IProphet synths.

Whenever I add an instance of one of these synths to a brand new project in Cubasis the CPU load spikes immediately (even before playing a note). When I try to play these synths through Cubasis using the keyboard the modulation wheel often starts jerking randomly and the Sustain button flashes on and off.

I have created a new project with a couple of Micrologue synths in it and they record and playback just fine. When I try to add one of the Arturia synths and then record I cannot hear the Arturia synth output and then playback is stuttering and awful across all tracks. The CPU reload remains extremely high.

I have searched this forum for some tips and have done the following: quit all other apps on the iPad; switched on airplane mode; fully restarted the iPad. None of these measures has helped unfortunately.

As standalone apps the synths work fine.

I am running Cubasis on an iPad Pro with 128GB (and over 50% free space) on iOS 9.3.5.

Any help or advice would be very much appreciated.

Thanks

Stephen

Duplicate, please refer to this topic:
https://www.steinberg.net/forums/viewtopic.php?f=183&t=101678