system browser tool

You could run the System Browser Tool in the ASRock utility for your unknown board, and see what it shows the link speed to be.

So your router has an optical input, and a standard RJ45 cable output to your board?

When you see the 10Mbps speed in the UEFI, is that from a cold start, with the PC shutdown? Does it show 10Mbps if you restart the PC into the UEFI?

My router has a 1000Mbps output that is then connected to an un-managed switch, whose output is 1000Mbps. This is what I see in the UEFI's System Browser tool:



So the System Browser tool in my board's UEFI is capable of detecting the transmission speed of the connected link.

You mentioned you may not have an IP address "yet" at that point? Meaning you have dynamic rather than static IP addresses?

If that is correct, your router may be in a low power state at that time, and running at 10Mbps.

When you are in the UEFI using the System Browser tool, check the two LEDs on each side of the network port on the board's IO panel.

The LED on the top/right is the Activity/Link LED. If it is on or blinking, a connection has been established.

The LED on the bottom/left is the Speed LED. Off is 10Mbps, orange is 100Mbps, and green is 1000Mbps.

I'm not sure on the optical detection. Unfortunately, I do not believe so. At least not from the perspective of you looking/it detecting from within the BIOS anyways.

bjlockie wrote: Shouldn't it default to reporting the highest speed the port can do?

hehehe, and then the next one would be asking why it "detects' 1000 when "all I have here is 100". See my point? Damned if they did, damned if they didn't. I honestly don't know.