Official Forum Representative
Thank you - it's been a substantial effort for the team. We're very glad that it came ready earlier than we were expecting.
I would love to know some more behind the design and decision proces, and why which compromises where made.
- Was a FinFET process considered and if so what killed it for this iteration (development cost, marginal costs, available IP, etc.)?
- This is the first time difference memory tiers of the same Pi are offered, what made you guys decide to go for multiple market levels?
- Double 4K monitor support is amazing. What made you decide on the two Micro HDMI connectors instead of one DisplayPort over USB Type-C for example? Could two regular HDMI sockets be stacked on top of each other?
- How much is the Pi ecosystem locked in on Broadcom? Will a Amlogic or Realtek chip in the future be possible for example?
- The SD-card speed increase is very welcome! Was an eMMC or M.2 slot considered?
- I would be very interested in a 'server' variant without the whole display, audio and wireless parts, leaving only the Ethernet and USB. Do you think such an product will be viable in the future?
- The current power usage is a lot higher then with previous generations, probably mainly because the way faster out of order CPU cores. Did you guys experiment with heat sinks and metal casings (used as heat sink)?
- A little of all of those, but primarily projected unit costs.
- Three things: we wanted to offer a $35 product; we could only afford 1GB of RAM at that price; and people had asked for (and our chip could address) up to 4GB.
- USB-C is rather a poor connector for high speed signals (Google "short to VBUS" for details), and we would have either needed to include protection silicon or put up with a substantial in-field failure rate. We did look at stacked type-A, but it would have dominated the board z height and we were a bit squeamish about the torque on the board when inserting the upper connector, and the EMC implications of routing high-speed signals to it.
- I think we're happy that the Broadcom silicon offers the right feature set, and of course total backward compatibility with earlier models.
- We don't think there's a compelling advantage to socketed eMMC over SD. M.2 would have been fun, but we didn't like the form factor considerations, and had no spare PCIe lanes. I think USB 3.0 SSDs are the way to go for high-performance storage.
- Possibly. The savings aren't particularly compelling (with the possible exception of wireless), so the rationale would have to be about form factor rather than cost.
- The intention is that "regular" users will be okay without an additional thermal solution, but I think that FLIRC-type metal cases will be useful for power users.