PRSfreak4
Power User
Plus many of the patches are constantly in the red output clipping zone. They sound like a speaker has blown or something, the volume changes are pretty wide too.
Check your Master level on your amp block. You tried clearing a preset and building a basic new Marshall-based amp/cab combo? I noticed that things only get better after firmware updates personally. Are you using Axe-Edit also? That will update your Amp/Cab/Effects library for you to visualize what could be going awry. Just curious.