I am guessing that is a big part of it, avoiding patent litigation is another. There are a zillion patents around GPUs that it is difficult to prove the someone

I am guessing that is a big part of it, avoiding patent litigation is another. There are a zillion patents around GPUs that it is difficult to prove the someone is using without more information about the internals. Back when I signed the S3 NDA/License agreement to get access to their underlying architecture there were specific clauses in that agreement that said I would agree to indemnify them if anyone brought patent litigation against them as are result of information I disclosed. It was unusual enough for me to remember it all these years later.