I used to check complex commercial PCBs specially those of graphics cards to see how professional PCB designers do their layout and learn from their techniques.
When I checked the card shown below I noticed two things regarding the placement of vias:
(A higher resolution image is shown here).
The PCB is surrounded by stitching vias all around the edges. What's the role of all of these? I think they're connected to ground to act as a shield, if that's true, I can't understand technically how by this placement they achieve this shield?
By looking closer to the mounting holes, I noticed they added vias all around the pad, why?