I am looking for a router that supports a UK mobile SIM data plan, not sure if there are any cheap OpenWrt routers or whether it is best to buy some fantastic model members here recommend and plug my existing router(s) into it?
I call BS on that. Just did a couple of tests on my 2016 laptop using the EM7455 modem it came with. Running Debian, ModemManager and Debian's 5.10 kernel with the cdc_mbim driver. Sitting indoors by my kitchen table and not trying to optimize anything. Got 220 Mbps using IPv6 and 180 Mbps using IPv4. Might be the different servers. I don't know of any other than the Telenor ookla instance doing IPv6.
i am using an old fanless atom pc with 2 ethernet cards as a router with OpenWRT in a remote site. By attaching a Huawei 3372s 4G usb stick i have Internet access in that site.
Make sure to get an unlocked version of that stick, or any other version. i got mine from ebay for < £20.
Thanks for that information, but surely that is comparing apples and pears, if this is the device you are referring to, it has a bus connection not USB, also I could not put it into the back of most routers.
I imagined that the M2 device has a faster throughput and that once you put it on USB that would limit the speed to the same as is likely if either were plugged into a Netgear or Linksys Router's USB port.
For some unknown reason, the m.2 wwan slot of my laptop (Thinkpad X1 Carbon 4th gen) only supports USB2 even though the EM7455 modem supports USB3. This surprised and annoyed me when I got it, as I was looking forward to finally be able to play with a USB3 connected modem. But in practice it never mattered of course. The modem is Cat6 (300 Mbps max) and USB2 (480 Mbps) is more than enough bandwidth.
As for USB cable or m.2 slot - there is no difference. If you have a USB3 adapter, cable and modem, then the bus bandwidth is 5 Gbps. That's still more than enough for most modems, even the 5G ones.
Some 5G modems have started using PCIe instead of USB. But I still haven't seen any test where this makes a difference. It might of course matter for other reasons than plain bus bandwidth. But so far it seems like the USB3 connected 5G modems are good enough.