If you open an old Matrox RT.X100 project using an RT.X2 installation, it opens as a standard Adobe Premiere project – without using any hardware acceleration, thus losing the entire point of the system. The answer is simple, but not documented anywhere:
Step 1: Create a new Matrox-based Project as normal
Step 2: Got to File, Import and import the old project (select Entire Project)
Now we have the project, but it still isn’t using the hardware or showing on the preview monitor
Step 3: Open old project sequence(s), select all and copy
Step 4: Open/create new sequence and paste the old sequence to the new sequence
Now the old project is using the new settings – simples!