I gave up 5 months of my new customer discounted Blast 200 plan last Wednesday to upgrade my service at full price to Gigabit. My Blast 200/10 speedtests were nearly always a solid 238Mb Down / 12 Mb Up any time of the day. I upgraded service to the gigabit plan online last Wednesday while at work. Rebooted my modem when I got home and found that I was now getting around 42Mb Upload speed (great), but download speeds were varying from 150Mb to 290Mb. Many times, I run speedtests (speedtest.org and speedtest.xfinity) and see download speeds under 100. I never saw that with with Blast 200 plan.
I have a Gigabit Docsis 3.1 Comcast certified Netgear CM1000 Modem (same one previousely used for blast 200 with solid performance)
Router is a Netgear Nighthawk X4S AC2600 R7800 Router (also same used for blast 200 with no issues)
I have tested speed from wired connections to the router, and wired directly to the modem. The fastest speed test results I have ever seen were a one time hit of 490Mb down. The next test immediately after that one was 203Mb down.
I'm feeling dissapointed and cheated.
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I have two seperate devices. A stand-alone modem and a stand-alone router connected together with CAT6 ethernet cable. I am seeing exactly the same erratic speeds when I unplug the router and plug the laptop directly into the modem. The modem doesn't have any routing (QOS/Firewall/Parental/etc) features.
However, while researching over the weekend, I did want to rule out the router (When it is connected) as a source of the problem. I turned off QOS, the traffic meter, the firewall, and OpenDNS parental controls on the router. I rebooted both the router and the modem with no difference in speedtest results. I started adding those services back in one at a time and saw no difference. This is a relatively modern fast router with a decent CPU that should easily be able to handle routing internet traffic over 1Gb without issues. It was easily able to handle the 239Mb speed I had before.
I re-checked speeds when connected directly to the modem last night and they appear to be identical to the speeds seen from the router when it is connected to the modem. The connection path for this test was "Coax cable coming into home -No Splitters" -> "modem" -> "PC plugged directly into modem's single ethernet port". There are no splitters involved anywhere in the house. Download speed tests when connected directly to the modem varied widely , but were generally between 150Mbs - 300Mbs. A single test last night briefly hit just over 500Mbs, but that was the only one. I assumed that due to congestion on Comcast's network at times, I would not always seen near Gb speeds, but didn't think I would never see the speeds. I have run tests all different times of the day including early morning. At this point, I think I will engage comcast support when I am sitting by the modem.
Thank you. A factory reset of the modem seems to have resolved the speed issues. I suspect something went wrong/was incomplete during the original comcast reprovisioning of the modem from my Blast 200 tier to the Gigabit tier. I'm now seeing upper 600Mbs to low 900Mbs download speeds when I run speed tests to speedtest.xfinity.com.
I appreciate your helpful suggestions!
I’m having a nearly identical situation with my recent upgrade from 250mbs to 1gig and wanted to ask you if your situation remains resolved? I had a tech come out and he told me there is no problem and that even when the speed tests say 90mbs it’s really still giving me 1gbs. 🙄. I have the Motorola MB8600 however I’ll try the factory reset tip.