Avid have finally announced support the Magma ExpressBox 3T pci-e Thunderbolt chassis is approved for Pro Tools 10.3.3 and a Macbook Pro laptop. This is the only combination that has been formally tested and approved but it is expected other Apple Thunderbolt computers will probably work.

You can now attach three Pro Tools HDX cards to your Thunderbolt equipped computer. The Magma ExpressBox 3T provides an ‘outside-the-box’ solution for using PCIe cards with Thunderbolt-equipped computers. And because Thunderbolt is also based on DisplayPort technology, you can daisy chain a high-resolution display with your Magma ExpressBox 3T. 

Now Avid just need to update their HDX compatibility charts which at the time of posting where still showing that the Magma 3T is not supported for Pro Tools HDX.