Did all these items work OK with OS4 and your MediatorSX as you have not made that clear.
I didn't think the spider or soundcards were functional with OS4 no matter what Mediator you used and whilst I understand you can get away with the Elbox drivers that was not advisable.
I've recently purchsed a Mediator TX and Radeon card so I'll see if they work with OS4.I've abandoned my Spider for a Subway and the latest version of Poseidon seems stable under OS4. Hope to use USB soundcard and ethernet with this device.
