I have a Mac Pro with two amd firepro d700 GPUs. Can I pull one of those GPUs out and stick it right into a Windows pc? Or did AMD make these GPUs specifically for Apple only?
These style machines (as pictured) are made with proprietary connections and components. The problem you'd have, even if you found a way to adapt the connection to a standard PCI-E slot, is that the drivers for the non-reference circuit board that chip is on do not exist for Windows.
Considering that these are GPUs on part with a modern $200-250 card like the GTX 1050 or 1060, I'd save yourself the heartache of wrecking your tech and just get a new card for the PC.