This is maybe not a yes\no answer. (this is not new to Vault!).
It depends on the job and what application is used to process the job.
For example, if you are updating the DWF for an Inventor 3D Model, this commands a headless version of Inventor called the Inventor Apprentice to create the visualization file. In this instance it will not use the graphics card, so adding a high performance graphics card won't improve performance.
However, it is possible to customise the Vault API to process other jobs like create a pdf. In that scenario, it would depend on the method and the application used. You'd best speak to the 3rd Party developer to find out how they do that, to get the answer to the question.