Ethernet Port does Not Expected Speed

I bought a Beebox3160 about 6 months ago and am wondering if anyone here can tell me if the ethernet port supports speeds higher than 250MB down.  I recently upgraded my internet subscription to 1GB down and 10mb up for work purposes (not using beebox for work).  I found that the Beebox only gets ~250MB down consistently, even after trying this with 3 different OS's (Win10, Linux Arch and Linux Mint).  I even bought a 1GB ethernet usb dongle that uses USB 3.0 and still got ~250 MB down.  Does the ethernet port or even the hardware itself support 1GB download speeds?  I'm ok if it doesn't, this is for my sanity and just accepting it doesn't support it.  BUT, if it does support 1GB down, what am i missing?

I set the port to 1GB on the router and on the beebox (in all 3 OS's)

I hardwired directly to the modem to eliminate the router and still got ~250MB down

Any help would be appreciated.

PeeJah