Why would Speed drop to 10 Mbps from 250 with Ethernet?

[username0475]

Spent Saturday pulling some Cat6 underneath my house to my PC from my router RT-AC68U (on Merlin).
Wanted to get off the 5Ghz WiFi adapter my PC was on & be hardwired.

Also - added an unmanaged switch to get more LAN connections for the DNLA TV & PoE cables I put in - also this weekend - but didn't terminate with equipment yet.

Saturday night speeds doing consistently 250's Mbps.
Feeling happy that everything was working as expected for both Ethernet & WiFi.

Sunday AM - speeds holding up still @ 250.
Went out to do yard work.
Come back in late afternoon & speeds are at 10Mbps on ethernet.
WiFi on mobile clients also falls down into the 10- 15 Mbps for both 2.4 & 5GHz.

I'm the only guy my street with Comcast.
I don't do anything beyond out of box settings with Merlin.
There was no power outage.
Rebooted the router 3x times - no changes in speeds.
Finally rebooted the modem & router & speeds came back.

What could have caused this?

 

[kab]

Could you clarify whether you are talking about LAN (data between two of your devices) speeds or WAN (e.g., downloads from internet sites) speeds? How were you measuring speeds?

 

[CaptainSTX]

Did you do your own terminations?

Regardless if you did your termination did you do a basic continuity and pinning check using a $10 tester?

On your router when the speed falls off what link speed is being indicated for the cable run?

Did you test the speed without the switch being between the PC and the router?

 

[ColinTaylor]

Rebooted the router 3x times - no changes in speeds.
Finally rebooted the modem & router & speeds came back.

ISP issue.

 

[username0475]

Could you clarify whether you are talking about LAN (data between two of your devices) speeds or WAN (e.g., downloads from internet sites) speeds? How were you measuring speeds?

Sorry I meant WAN. Speed test from Xfinity site.

 

[username0475]

Did you do your own terminations?

Regardless if you did your termination did you do a basic continuity and pinning check using a $10 tester?

On your router when the speed falls off what link speed is being indicated for the cable run?

Did you test the speed without the switch being between the PC and the router?

In order of Question:
Yes.
Yes.
n/a
Yes. - Same.

 

[username0475]

ISP issue.

Appears that way now...
Odd that it happen on a Sunday afternoon.