NETGEAR CM400 (8x4) DOCSIS 3.0 Cable Modem. Max download speeds of 340Mbps. Certified for Xfinity from Comcast, Spectrum, Cox, Cablevision & more (CM400-1AZNAS)

NETGEAR CM400 (8x4) DOCSIS 3.0 Cable Modem. Max download speeds of 340Mbps. Certified for Xfinity from Comcast, Spectrum, Cox, Cablevision & more (CM400-1AZNAS)

Price: $44.99 Details

Availability: Usually ships in 24 hours
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22 new or used available from $33.00

Average customer review:
(4.0 stars, based on 1902 reviews)

Product Details

  • Size: Up to 340 Mbps - (8x4)
  • Color: Black
  • Brand: NETGEAR
  • Model: CM400-1AZNAS
  • Published on: 2015-07-07
  • Released on: 2015-08-17
  • Dimensions: 2.05" h x 7.17" w x 9.46" l, 1.17 pounds


  • Compatible with Xfinity from Comcast, Spectrum (Charter, Time Warner Cable, Brighthouse), Cox, CableONE & more.
  • Not compatible with: Verizon, AT&T, or CenturyLink. Not compatible with bundled voice services.
  • Cable Modem only (no WiFi router)
  • Recommended for all speed tiers up to 1Mbps. Separate router required for WiFi. 8x4 channel bonding.
  • Ideal for streaming HD videos, faster downloads, and high-speed online gaming
  • DOCSIS 3. Cable Modem with 1 Gigabit Ethernet port. DOCSIS 3. unleashes 8x faster download speeds than DOCSIS 2.

The NETGEAR CM400 High Speed Cable Modem provides a connection to high-speed cable Internet, up to 340 Mbps. It is Cable Labs certified and with DOCSIS 3.0 is 8X faster than 2.0. It is compatible with U.S. cable Internet providers like Cablevision, Cox, Time Warner Cable, XFINITY & more.

Customer Reviews

Most helpful customer reviews

204 of 221 people found the following review helpful.
5No more cable modem rental fees for me!!
By Christopher Malone
It was time to start trimming my Time Warner Cable bill. So, I purchased this puppy. Yeah, it has a cheap price tag, but this little baby packs a punch. I pay for the Extreme package via Time Warner. I was averaging 80 megs down. After installing this and getting it activated, my download speeds are averaging over 115 megs down - that's both wirelessly and hard-wired. The setup is simple. 1. Remove your current cable modem. 2. Put this one in it's place. 3. Hard-wire it to a laptop or a desktop (yellow cable to the yellow port on back of cable modem, the other end to the internet port on your laptop or desktop. 4. Power on the modem (making sure you have already connected the coaxial cable as well. (When the globe stays a solid green with no blinking, it is recognized as being connected. 5. Turn to the activation page in the mini manual that comes with it. It will show various internet providers and their perspective links. 6. Open up a browser (with pop-up blocker offf) and follow the prompts. Odds are in favor you will get "due to your account settings, this will not work - call the 1-800 number shown." That's okay, call it. Tell the operator you are installing your own cable modem. The operator will ask for the MAC address (found both on the box and bottom of cable modem). Agent on the phone will first remove your current cable modem from your plan (or else, this will never work). You will power it off upon request, and back on again 30 seconds later. Go to a website of choice - and wa-la, you are back online!! No more cable modem rental fees!! BTW, I work in the IT field, and have for 25 years. This will be all the modem you ever need unless you plan to go over 450 megs in the future. I have the following items that may be online at any time and all at once: Xbox One, PS3, Two laptops, One desktop, one cell phone, and one tablet. I can play Netflix on all devices (4 at once since that's my Netflix account package), and there is no buffering at all. I bundled this with the Netgear WNDR4500 Dual Ban Gigabit Wifi Router. Here's my layout. Cable Modem feeds the router. The router feeds my 16-port switch. I work on computers on the side, so the switch comes in handy. Any questions? Feel free to ask me. Trim your cable bill and get this or any cable modem for that matter. Note, this is a cable modem only that does not supply wifi. It only has the internet-out port. There are no other ethernet ports on it. So, upgrade your router or get one. The model I mentioned above is a great match. You are welcome!!

21 of 21 people found the following review helpful.
5This is so fast!
By Greg L.
Speed test indicated 88mbps (I am paying for 75 btw). This is an immediate improvement over my older Motorola modem that was only cranking 20mbps. So finally getting my money's worth!

****SET UP****
I had some trouble getting this to work initially, and while there are instructions, they don't tell you how to activate the actual modem itself (it only tells you how to activate with your service provider). You need to plug in your laptop directly to the modem and go to the router login (I think and log into that and activate from there. Once you log in, its pretty easy. Then you're all set. It would be nice if they included that in the set up info.

0 of 0 people found the following review helpful.
5Easy to install; however, language issues became the challenge.
By Amazon Customer
Easy to install. My only challenges were Comcast Technical Support. The Cable Modem was not the problem. It had nothing to do with the Comcast's technicians qualifications; it was more a human communication problem. I understand that we live in a world economy; however, for resolving technical issues, it sometimes is easier to communicate with people who understand what both sides are saying. Just speaking the same language doesn't mean that people understand what you are saying and they understand you. It is challenging enough to get the equipment operational and more frustrating when communication becomes the main issue. The problem they had establishing my internet connection was the technician had an issue with the MAC ID. I had too many numbers that were the same. She wrote down 8 numbers and missed 4 numbers ..... was done in by too many 6's (lol). I asked her what her problem was and she finally told me and at that point were able to fix the problem.

See all 1902 customer reviews...