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)

List Price: $44.99
Price: $39.99 Details

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

Average customer review:
(4.0 stars, based on 2029 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


  • Support Cable Internet Service plans up to 100 Mbps. Separate router required for WiFi
  • DOCSIS 3.0 Cable Modem with 1 Gigabit Ethernet port. DOCSIS 3.0 up to 8x faster download speeds than DOCSIS 2.0
  • Not compatible with: Verizon, AT&T, or CenturyLink. Not compatible with bundled voice services
  • Compatible with Xfinity from Comcast, Spectrum, Cox, CableONE & more

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

230 of 248 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!!

1 of 1 people found the following review helpful.
5Don't pay a monthly fee to "rent" your cable company's modem...
By Doug
Bought this so that I wouldn't have to pay that stupid monthly "rental fee" to my cable company to use theirs. Very easy to install, but that may be contingent upon your cable company and whom you happen to get on the phone with from customer service, because I did need to call to activate it. I might've gotten lucky, but the whole process went really smoothly for me and it works great!

0 of 0 people found the following review helpful.
5Great Buy
By H. Hun
I'm capable with technology but no real tech here. I know how to configure modems and routers and work at a large retailer of tech, so I see a lot. I did a lot of research when getting my new modem and router, while also being on a tighter budget.
While I don't know the high techie techie stuff, this has been working really well for my family for the last few months. No lag or failure. Only had to power cycle set up once and I don't think that was modem's fault. Happy with product.

See all 2029 customer reviews...