TL;DR: Do NOT buy this modem if your Intenet connection is through Xfinity/Comast and you live in an apartment complex. I recommend the Arris S33v2 instead. I live in an apartment complex and needed a new modem as my previous Surfboard would reboot at even the slightest bump in power that not even a Sinewave UPS could stop. The Motorola MB8611 was consistently in the top 5 best modems for all 14 reviews sites I looked at so I purchased it. Package did NOT look like it had been returned...everything was accounted for and the box/plastic bags were sealed. Setting it up was pretty easy, but after a month and a half, the modem would suddenly reboot with no warning. No power issues...nothing obvious. The first time, I ignored it and went about my day. The second time was two weeks later and the Comcast representative said that there was some work in my area that would continue from Thursday through Sunday. The modem rebooted a few times during those 4 days, then was fine until the next weekend when it started rebooting again. Called Comcast...they blamed the modem. Did some research and discovered that the Modem firmware (aka Software by Motorola's terminology) CANNOT be updated by consumers...updates to the modem are sent to Comcast by Motorola, Comcast is supposed to test them, then Comcast pushes out the update to your modem EVEN IF YOU OWN YOUR MODEM. Called Motorola support number, put on hold for 45 minutes, then disconnected. Tried Chat...after 30 minutes, got an automated chat message saying I would be emailed. Got the email and responded...over the course of a week, I sent them screenshots of logs and statuses of the various channels. Motorola's response was that according to the logs and status of the channels, the power for the OFDM channel was too "low". Most of the other channels had between a 1 and -2 power level, but the OFDM channel was -11 to -13. Motorola claimed that the difference between the OFDM channel's power and the other channels should not be more than 10 or this could cause the modem to reboot. Contacted Comcast and had them send out a technician who replaced the cable up to my apartment and the cable up to the modem. He said that Motorola isn't making sense...that if one channel goes down, the other channels are there to pick up the signal so you don't lose internet. As Comcast did not view this service as necessary, they charged me $127 for it. After the service, ALL channels power were shifted up by about 3...I was getting power levels of 1 to 4 on all channels except the OFDM channel which was now between -7 and -10. Two weeks later, the Motorola modem started rebooting again. Tried to contact Motorola...again 45 minutes on the phone resulted in a disconnect. The chat did not automatically send me an email and using the email from my previous issue resulted in no response. All of this was within the 90 day warranty. Instead, I purchased the much cheaper and also highly recommended Arris S33v2 modem. I don't like the fact that it literally has only ONE light at the bottom, but the setup was just as easy. Since then, I have had NO reboots or service interruptions for more than 4 months. Power levels are about the same...the OFDM channel still fluctuates between -7 and -10 and the other channels are all at power 0 or 1. I found that when the light on the Arris changes from Blue (normal operation) to Green, I STILL never lose internet and when it is in this state, the OFDM channel is gone from the list. When the light returns to Blue, the OFDM channel returns in the status. So either Motorola is lying about how important the OFDM channel is, or their MB8611 modem is far too sensitive with regard to the OFDM channel and the loss or disconnect of that channel manifests as a reboot. I DO NOT recommend this modem for use with Xfinity/Comcast if you live in an apartment complex. Read more

Works perfectly with no issues. Read more

Pays for itself in less than a year. Read more

MB8611 purchased mid 2020 to replace an old Zoom DOCSIS 3.0 modem. Modem has been connected to a Linksys WRT1200ac router running regularly updated DD-WRT firmware since purchase. Both modem/router are sitting behind a small APC battery backup/surge protector (BE600M1). This review is for the MB8611 only and should not be considered valid for the MB8600 or MB7621 nether of which I have purchased/knowledge. The MB8611 was a little higher priced than I hoped but a $50 gift card helped ease the pain. I did lots of research and found the MB8611 was the best fit for my setup and future service upgrades. My Zoom modem was maxed at 343 Mbps DL where as the MB8611 could handle up to 2.5 Gbps which was nearly double what my router can handle. When MB8611 was purchased my service was 100 Mbps, ISP upgraded me to 200 Mbps and with this last ISP upgrade now sits at 300 Mbps. (none of the upgrades were requested) Confirmed all accessories were present so I unboxed and hooked it up. I was surprised to have an active internet connection within a couple of minutes after boot completion. Feeling uneasy about the nearly instant connection I contacted my ISP via phone and went through the process of registering my new modem's MAC address. It may not have been necessary to do so but I felt more confident about a continued connection once my ISP confirmed they saw the new modem and registered the MAC address. BTW, I had checked prior to purchase and found the MB8611 had been newly added to my ISP's list of approved user modems. I was concerned the first couple of weeks but basically have ignored the modem since. After approx 2 yrs I thought I should share my experience. The MB8611's performance has been amazing. The router is rebooted every night but the modem has not been rebooted since purchased. I've had a couple of connection drops but quickly confirmed my ISP was off-line in my area temporarily. With three wired and ten wireless devices the MB8611 has been rock solid. It just works without any intervention from myself. I consider it one of my best investments. The modem sits on top of a file cabinet next to my router. Placing my hands on the sides at the top it is slightly warm and cool at the bottom. I was using QoS on my router but disabled it to try the modem's Active Queue Management (AQM). With no apparent change in performance I left the router QoS disabled. The modem lights are on solid except for the bottom LAN connection light which blinks constantly. That may be a negative for some? I highly recommend the MB8611. It has been the best modem I've owned to date. I have attached a page from the MB8611 manual that explains the lights color/blinking/status. The modem lights image to the right is my modem's appearance connected to a 300 Mb service. I've also added the rear view of the three similar modems to indicate what the MB8611 back view is (left) compared to the other two available on the MB8611 Amazon page. Read more

Easy to setup with Xfinity, works great. Was up and running within about 20 minutes with Xfinity, zero problems. Read more