I have a CM400 modem, which has a specified max speed limit of 340Mbps and today my ISP (Xfinity) upgraded my plan to 600Mbps down, 20Mbps up, but I was surprised to see that the max download speed I could get was around 270Mbps.
Of course I knew I would never get the full 340Mbps download speed, but I expected to get at least 300Mbps and certainly not a max of only 270Mbps, so my question should be pretty obvious. Why am I unable to archive a higher download speed?
Note:
- I ran the speed test using several websites and several passes on each site not just one site or one location.
- I also I also used 2 different browsers with no extensions / addons installed on them.
- I have a pretty good system (8700K @ 4.8Ghz, 16Gb 3200Mhz Ram, Crucial 525GB M.2 NVME Drive, etc...) so there should not be any bottlenecks there.
- My firmware should be the latest version available, but my ISP would know more about that then I would.
- My network cables are all Cat6e so they should be able to handle the speed/load.
- I have a VPN, but I did not have it enabled during the test.
- I contacted my ISP to double check that my modem was provisioned with the new speeds, which was verified by the upload speed test showing the newly provisioned speed of 20+Mbps (prior to upgrade it was only 10Mbps).
- I connected the modem directly to the cable line coming out of my wall (i.e no splitters) to eliminate the possibility of a bad / low quality splitter getting in the way.
- I am sure I did some other sanity checks, but at 4am I kinda forget everything I tried, but I should have covered all of the basics.
Anyway, if anyone has any other suggestions (short of buying a new modem) I would be happy to hear them.
