Long time ago, a SHIELD product was advertised to combine as an expansion, it is an I/O Expansion board kit which can be plugged on Udoo Bolt by using the horizontal CN24-CN25 Arduino Pinout 40 pins.. Could someone tell me where I could find even through net searching it gives no results and not even similar. I have to submit another topic concerns the GPU .. I ask the technicians to indicate a video card as it was done in the past, in fact I recovered the project but, development has progressed much faster today there are more performing undated CPU cards. About the Arduino low voltage and Arduino high voltage problem, how is it possible to recognize and not make mistakes on shields and groves between 3.5V and 5V ???
Q1 --> that IO Shield, if not in UDOO's eShop, probably it is no longer made. Q2 (newer GPU) --> it is always a tradeoff (more GPU power but consumes more energy/generates more heat) and whether or not it's an overkill (low spec CPU with a higher spec GPU???) Q3 (Arduino shield type 3.3V or 5V type?) --> ask the seller the question (only the manufacturers know and let them publish their module's spec)
About Q2, you could add any PCI-e card, but the Bolt has PCI-e x4 Gen 3 interface, which for example if you would add an nVidia 3080 on it, for example, it would boot up and work normally if you power it properly, but would not be enough to feed it data at a proper rate to fully use it.