It’ll be tough because you would need a dedicated PCIe x4 bus and above. I’m not sure many of these low power CPU would support that on top of supporting a SATA bus. Zimaboard has a PCIe expansion slot but it’s limited to 6.0 Gbps (guessing they use the rest of the bandwidth for something else like storage).

You can increase your bandwidth if you have a multiple NIC computer though. You can tie in 2X 2.5Gbps to get about 4 Gbps to your switch.

Edit: assuming you mean 25G and not 2.5G?

There's plenty of bandwidth despite the limited number of lanes; I'd think with a PCIe switch everything would be just fine...

They have limited PCIe lanes. The N100 I ordered has a 2.5GbE and from what I can see only a x2 M.2 M-key slot. However that should be sufficient for a 10G adapter, so while perhaps janky you could try to fit one of these[1] in there.

Will have to resort to the 2242 M.2 SATA slot for storage though, or the USB ports.

[1]: https://www.aliexpress.com/item/1005005065403928.html

LattePanda has PCIe slots, if you prefer: https://www.lattepanda.com/blog-308782.html

2.5gBE devices are also becoming more mainstream (Like Orange Pi 5 Plus, Radxa Rock 5).

The main problem is not the interface in most cases, but the internal bandwidth on these boards.

I'll be spinning up an Orange Pi 5 with 8GB of RAM as a home server shortly. Let's see how it goes.

I'm not really talking about the little "Pi-class" ARM SOC boards, but more the "edge compute" type hardware market that might be served by a small stack of NUCs. The internal bus on the Pi's SoC maxes out at 3.6gbps; it's clearly a non-starter for a high-IO project, but there are plenty that would be highly serviceable.

100gbe is already pretty affordable, like Mikrotik's switch. Not an overkill considering a single consumer NVMe drive cam do ~50 Gbit/s.

One 100G QSFP28 module costs about $100. 100g Mikrotik CRS504-4XQ-IN switch costs about 600-700 bucks.

Consumer PC mainboard side the problem is often insufficient PCIe lanes. Except in server products...

I just want 2 decent nics, 2 nvme, 8-16gb ram, and a cpu, that's all. Damn thing can be headless for all I caree.

Instead all these boards all have six video outputs and usb connectors protruding from every single edge. No shit you don't have any PCIe lanes left after you spent it putting three 10gbps usb ports on the front. Is it just because they can?!?

I'd like 100 gigabit ethernet, 128 GB ECC, 4x NVMe and still enough PCIe lanes for some GPU for ML.

Seems to be impossible without going to server mainboards.

You seem to be aiming a bit above what I am after. Almost any AM5 board would get you there with a couple of PICe cards though. Dont think I've ever seen a board with "onboard" 100GBe; the high end has mostly moved to OCP3.0. There is one single board computer that has an OCP3 slot which is actually a pretty nice idea for SBCs; perhaps we will get something similar to the R86S but with a more powerful cpu and some additional storage io soon.