The device is very... very interesting.
First of all the BPI-R3's communication to its four-port switch is internally limited to 2.5Gbit. Which for normal use isn't a huge limitation, since it has no single connection greater than 2.5Gbit. But it's nice if your four port GBE switch can actually handle 4Gbits to the CPU so that the board can serve up data to all clients with no bottlenecks.
The BPI R4 eliminates that bottleneck. The R4's Filogic 880 has three internal MACs. The first MAC is connected to the four-port switch and can handle the full 4gbit/s of that switch. The other two MACs are 10gbit and connected to the R4's 2 x SFP+ ports via USXGMII.
Besides that the other points about the board making me anticipate it greatly are:
- The R3's SoC is already pretty impressive, with 4-core A53 @ 2GHz. The R4's Filigoc 880 is 4-core A73 at 1.8GHz. That's a two - threefold increase in computing power.
- 4GiB RAM - the R3's 2GiB already made it a very useful device for much more than just as a router (I use mine as a general purpose server), so double that and it's a very interesting device
- The M-key m.2 interface on the R3 and R4 are nominally only for NVME SSD. But I've tested my R3's interface with all sorts of things, including various mPCIe and PCIe boards (via form adapters) and it works with most. I have no reason to expect the R4's m.2 will be any different.
There are a couple things on my concern list though, and they all concern the mPCIe WiFi 7 daughter board.
- The placement of the daughter board under the main board is going to be something you need to be very careful with thermally.
- The daughter board shown in pre-release has a 4T5R WiFi 7 6GHz radio and 4T4R radios for both 2.4GHz and 5GHz, with an added dedicated antenna for DFS detection. That's fourteen antennae. That's a recipe for terrible mutual interference, even just through the way one antenna (even if it's not being transmitted on) will passively shape the signal of another. Fourteen antennae on one device requires some serious thought and attention given to their placement. That's the ham radio experience in me talking.
I suggested to @BPI-SINOVOIP that they combine the 2.4GHz and 5GHz radio outputs on the daugher board with signal mixers to give 4 x 2.4+5GHz antennae and 5 x 6GHz antennae. That is a much more workable scenario, given how easy good dual-band antennae are to get. I suspect they are already too far along the development cycle to be able to though, but we'll see.
To address both points #1 and #2 above, I also recommended to them a case with the following characteristics:
- Vertical orientation. A horizontal orientation will just trap the heat of either the main or daughter boards and require mechanical ventilation (something I don't like in a router that you want to put somewhere and forget)
- Ventilation slots on the top and bottom, to allow good air flow up and then along the vertical surfaces (and heat sinks) of both the main and WiFi daughter boards.
- Thought given to internal cable routing.
- RF-transparent plastic, so as to be usable with internal antennae. Not all plastics are equally RF-transparent. Acryllic and ABS are both good choices.
- Two or three internal antenna mount-points along the "flat" of each vertical side so that two or three of each band's antennae can be internal ones with signals directed out the sides. This will improve overall coverage and reduce mutual interference.
- Sufficient mounting holes along the edges so that two or three of each band's antennae can be good external ones you can alter the orientation of.
With Banana Pi, their cases tend to be an afterthought. I have not yet bought a case from them that I have not had to alter or machine to add either antenna or ventilation holes to. BPI has in the past wanted to encourage third-parties to buy their boards in quantity to put together with their own cases. They really want to be an OEM for someone else. This has so far not really materialized, so I encourage them to give more time and attention to their cases.
That-all said, some of my reservations stem from the fact this board is almost too good. 