@RunPlayHike 

The C4000 has a SPEED test built-in, right on the main page. What does that show?

Are both cables Cat6 or better, 5e might be OK as well?

Do you get that speed on all devices (if you have others)?

@IrvSp speed using the internal test using the tether app are between 400-600mbps it varies. 

3071792

RunPlayHike wrote

@IrvSp speed using the internal test using the tether app are between 400-600mbps it varies. 

@RunPlayHike 

What speed service did you have before?

Have you rebooted via power down/up cycle of both the modem and router in order?

For what it is worth, I used Tether and did the speed test and then opened the Browser and my A20 did show the test was done a few minutes before. So either way would have the same results.

Note, the A20 and C4000 are basically the same device. However, I only have 400Mbps service. Spectrum does about a 20% over provision, so the best I can get is in the high 470Mbps down. I get that both wired and wireless with no problem.

I'd expect a solid reading though, not a varying one, which to me indicates a problem, either in the router, cable (have you tried a different one?), or some other source like interference?

Do you have the latest F/W installed?

Lastly, nothing helps, I'd contact Support on this.

@IrvSp Went from 400 mbps service to 900.  Previous modem was a cm600.  New modem is cm1000 v2.  I connected the PC directly to the modem and i get over 900 mbps on every test.

As soon as I connect the modem to my router, and then run the same cable that I used to directly connect the modem to the PC, my speeds drop to roughly half in most tests. The link speed on my ethernet link shows 1000/1000 and the internal router speed test is also usually getting between 500-600.  So somehow the router appears to be the culprit in the slower speeds.  I have replaced tried different ethernet cables between the modem and router.  Will try support next!