netgear c7000 modem router only gets 40mbps speed

[corvairbob]

i jsut got a new netgear modem router c7000 that has good reviews. but mine is only getting 40mbps on a regular basis. every now and then it see over a 100mbps but not very often.

i just took a c3700 offline because it was giving me this site is not safe warnings that i never got before and this happened after i had a power outage. and all of a sudden i was getting these warnings and not able to get online. comcast did not have a fix and gave up.

so i got this modem said to be new out of the box, it turned out it did have an account hooked to it and comcast did finally get that removed and put me on it. but the c3700 modem router got over 100mbps every single time i tested it. this one can get at best 95% of the time up to 40mbps.

seem the netgear community has not clue and netgear will not help. so maybe someone here has an idea? i'm not looking at another new in the box sealed c3700 modem router to see if a new in the sealed box will get back to 100mbps and more. but maybe someone here has an idea. both modem have the same error event logs with a critical 3 ranging Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=a0:40:a0:39:76:b0;CMTS-MAC=00:01:5c:71:3e:5b;CM-QOS=1.1;CM-VER=3.0; thanks

 

[COLGeek]

Is this your device?

https://www.netgear.com/home/products/networking/cable-modems-routers/C7000.aspx

When you set it up, did you update the firmware to the most recent version?

Also, how are you measuring its speed? From wired or wireless devices?