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Linksys High Speed Cable Modem, DOCSIS 3.0 8x4


Maximize Internet speeds to your WiFi router with the Linksys 8x4 Cable Modem (CM3008). It delivers stable high-speed connectivity for existing Internet service plans up to 100 Mbps.* Your household will enjoy awesome WiFi in no time with its easy setup.

Note: Cable customers with Internet speeds of up to 300 Mbps should use the Linksys CM3024 Cable Modem.


Owning your own modem allows you to eliminate rental fees from your service provider. The Linksys CM3008 Cable Modem is certified to work with Internet service plans from major cable providers, including Comcast Xfinity, Time Warner, Cox, and Charter--providing savings up to $120 a year on modem rental fees.

How the CM3008 Cable Modem Works


Maximize the data transfer speeds of your current Internet service plan with eight download and four upload bonded channels on the CM3008 modem. These multiple bonded channels enable you to optimize media streaming and file transfers using the CM3008 by simultaneously transferring large amounts of data over many channels. The result is more effective and efficient usage of your existing cable broadband connection.

Additionally, the CM3008 has a slim, compact design that allows you to place the cable modem with your router, and maintain a clutter-free surface area.

DOCSIS 3.0 Speed Chart


Certified for DOCSIS 3.0 cable Internet standard, this powerful modem can handle high-bandwidth transfer rates over existing cable lines with speeds of up to 343 Mbps.*

Intel Inside


To achieve high-speed downstream and upstream performance, the Linksys CM3008 Cable Modem features an Intel Puma 5 chipset. Designed to be a flexible and high-performing solution, the Puma 5 chipset will facilitate cutting-edge data service offerings as technology continues to advance.


To use the Linksys CM3008 Cable Modem, simply follow this three-step process:

Step 1 Plug modem into a power source

Plug modem into a power source

Step 2 Connect modem to wall jack

Use the coaxial cable to plug modem into wall jack

Step 3 Connect Ethernet cable

Connect Ethernet cable from modem to WiFi router

Technical Specs
  • Cable (DOCSIS) Standards:
    • DOCSIS 1.1 Certified
    • DOCSIS 2.0 Certified
    • DOCSIS 3.0 Certified
  • Network Standards:
    • IEEE802.3
    • IEEE802.3u
    • IEEE802.3ab
    • IPv6 support (Internet Protocol Version 6)
  • Ports:
    1x Gigabit Ethernet
  • Maximum Line Rate:
    Up to 343Mbps Download, Up to 120 Mbps Upload
  • LEDs:
    Power, DS (Downstream), US (Upstream), Status, Link
  • Buttons:
  • Power:
    12V 1A
  • Interfaces:
    Cable: F-type female 75 ohm
  • Warranty and Support:
    • 1-year limited warranty
    • 90-day complimentary assisted technical support
Package Contents
  • Linksys 8x4 DOCSIS 3.0 Cable Modem, CM3008
  • Quick Start Guide
  • CD-ROM with Documentation
  • Ethernet Cable
  • Phone Cables
  • Power Adapter
Rated 5 out of 5 by from Nice upgrade to dated Motorola SURFboard SB6121 After 7 years of using the SB6121, it was time to double the bounded channels in order to get the most performance out of our Cox 100Mbps Internet connection. With the new CM3008, the performance is great with an effective 15% speed/stability increase. The smaller physical size and more efficient power draw of this little beastie thanks to the Intel chipset is also a nice plus. Overall, the cost is reasonable and the upgrade is noticeable. It is a great companion to the Linksys WRT1900ACS spearheading my home network setup.
Date published: 2016-07-17
Rated 5 out of 5 by from Compact design, easy set up and works great! I was looking to upgrade my cable modem and eliminate the equipment charge from my cable internet company (Comcast). My existing cable modem was 8 years old so I hoped to find a new modem that would provide higher download speeds and save me money. I got the Linksys CM3008 and was amazed at how easy the set up was - basically: power everything down, attach cable lead and ethernet cable to modem and router, start up modem and router, then start up computer. After opening a browser, I was taken automatically to the modem set up page, where information is entered to connect the modem to your provider. The longest part on the installation (by far!) was calling Comcast - their system doesn't allow online cable modem set up. I gave them the modem model number and Mac address, and I was online. I immediately ran a speed test and found that my download speed had improved by 12%! No problems at all since installation 2 weeks ago. I highly recommend this CM3008 as a cost effective, compact and efficient cable modem!
Date published: 2016-06-09
Rated 5 out of 5 by from Easy Installation I received this modem a couple of weeks ago. It was easy to install and automatically connected with my router. If your service is with Time Warner Cable you will have to call them to reestablish your service with the new modem. Only took a few minutes to get back online.
Date published: 2016-06-12
Rated 5 out of 5 by from Excellent Product Cox communication tech specialist said it was the strongest signal she has seen on any modem she has activated!!!
Date published: 2016-06-18
Rated 5 out of 5 by from Works Great Works great , does exactly as stated. I set it up in less than 5 minutes. One little thing, In step 6 of the Quick Start Guide it says that once the CM3008 is ready the Ethernet LED will be steady. well it never did light steady, hasn't yet, And I don't think it ever will. but that don't bother me none, Just thought I'd mention it. Works great. I'm very happy with the CM3008
Date published: 2016-06-14
Rated 5 out of 5 by from Linksys CM3008 easy setup with Comcast/Xfinity I am pretty well acquainted with Comcast/Xfinity cable modem. I am replacing my rented Xfinity with the NEW Linksys CM3008. !. I got the CM MAC address and serial number from the back of the Linksys CM3008. 2. I hooked up the Linksys CM3008, via ethernet to my WiFi router, connected the Comcast cable to the Linksys CM3008 and finally plugged in the power. 3. I called Comcast/Xfinity tech support (800) 934-6489 and asked for modem activation. 4. I supplied the tech with my personal information for my account and told them that I was activating a "personal" (versus leased/rented) modem. 5. I told the tech the Linksys CM3008 CM MAC number and the serial number. 6. The tech checked the network and saw my Linksys CM3008 and registered it on their system. Then they took about four minutes to send a firmware update and reboot the modem (to fit their system). 7. I rebooted my WiFi router and I was on the internet. Total time from unboxing the Linksys CM3008 to getting on line took about 20 minutes. My only issue with this tiny modem was the light weight. I got it set between a shelf and the router. I set the Linksys CM3008 on it's side. The Power and the Status LEDs are green, the other three are blue (Ethernet Led blinks when there's traffic)..
Date published: 2016-05-31
Rated 4 out of 5 by from Issue Connecting To TWC - Finally Got It Working Well, I gave them a bad review before and want to come back here and make it right for them. I returned the item and exchanged it for a new one. Hooked it up and called TWC for activation. It was not working as before. I finally used the network cable supplied with the CM3008 and voila, it worked on my direct connect computer. However, no Wifi from my router. After searching, I did a factory reset on my Wifi router and everything is working now. Thanks.
Date published: 2016-10-15
Rated 4 out of 5 by from Good,basic modem Internet providers charge you a rental fee for their modems so owning your own is, in my opinion, the best way to go. The CM3008 is a good, basic modem that was very easy to set up. I simply followed the directions and was online in less that 15 minutes. I already have a Comcast account so I used my login and password rather than my account number. I would suggest using Chrome as a browser since both Microsoft Edge and Internet Explorer seemed to hang after logging in. My speed tier is 25 Mbps and I clocked in at 29 Mbps with this modem. I have it connected to a Linksys EA 8500 router. I am unable to access the modem via it's GUI interface due to a Comcast restriction, but the upstream and downstream lights show blue indicating that the upstream and downstream channels are bonded. This modem should suffice for speeds up to 100Mbps.
Date published: 2016-06-12
Rated 5 out of 5 by from Compact Design & Good Performance For the short time I've been running this device it has delivered reliable speed matching my previous, more expensive modem. As the title indicates, this modem has a compact design considerably smaller than others. The only setback I had experienced during setup was the fact that my ISP's online activation didn't work with this device even though it is on their approved device list. However, with a relatively short phone call I was up and running.
Date published: 2016-06-16
Rated 5 out of 5 by from Compact!! Received the unit as a complimentary sample. In return, I had to give my unbiased impression and my own performance findings of said cable modem. The unit is very compact compared to previous cable routers I’ve owned in the past. This is a plus for me since the unit besides being small, is very light and can be attached under a shelf or hidden behind a cabinet via Velcro strips. The top of the unit has a perforated grid in order to help heat scape and keep the unit cool while under operation. Next to this grid, you will find 6 LEDs indicating that the unit is on, connected to the Internet, activity up/activity down and so on. The only thing that this unit does not have is the capability to connect a phone should you need to have a landline. While this is not a fault finding towards this model, perhaps the manufacturer did not have this in mind for this unit. It will be nice to see such option on future models if their goal is to compete with units currently available in the market with such feature. This modem is powered via a power supply that you plug to the backside of the unit. I found its performance to be on par with my current cable modem and I did not find any issues during the 10 days that I had it running on my home network. I’d recommend the unit if you are looking for a small/compact cable modem and have no need for a VOIP phone.
Date published: 2016-06-18
Rated 5 out of 5 by from It is a great basic unit! I received a free evaluation cable modem and installed the modem into my existing system which is comprised of modem and wireless router. I removed the existing Cisco CM3010 and installed the CM3008 in its place. I love the size of it. It works well as a standalone cable modem, but I was disappointed that it did not have the output for an USB like the CM3010 that the service provider supplied. For a basic modem it is a great little unit!
Date published: 2016-06-27
Rated 5 out of 5 by from Great compact modem I received the CM3008 DOCSIS 3.0 Modem several weeks ago and wanted to be sure that I didn't have any problem's before writing a review. I've gotta say that I have been thrilled about it's performance! The DOCSIS 3.0 modem that it replaced suffered from an occasional freeze and have to get rebooted every once and awhile. Do yourself a favor and pick one up if you are in need of a DOCSIS 3.0 Modem! You wont be sorry.
Date published: 2016-06-19
Rated 4 out of 5 by from Its works as a standalone cable modem. I love the size of it. It works well as a standalone cable modem, but if you really wanted to replace the modem provided by your service provider you will be disappointed because people often have their phone services along with their Internet which means you need to plug your phone to the cable modem. Until there is a cable modem with phone jack, then you can truly replace the modem with a third party cable modem.
Date published: 2016-06-14
Rated 5 out of 5 by from Easy to install I received the CM3008 for free to test and review. The CM3008 is compact and should be able to fit anywhere. It comes with a good quality Ethernet cable. I followed the 3 step quick start installation guide and had the modem connected to the internet in just a few minutes. The first 2 steps deal with connecting the modem the internet and your router. The 3rd steps deals with activating the modem with your provider. After I made the connections, I opened a browser (step 3) and it took me directly to TWC's activation page. I filled in the required information ( step 1 in the installation guide tells you what you'll need) re-booted and that was it. Reconnected immediately and has been running perfectly since. Between the easy installation and the cost, the CM3008 is a good value not only for those renting a modem but for those that may have and older modem too.
Date published: 2016-06-14
Rated 5 out of 5 by from Better than renting a cable modem forever Linksys CM3008 DOCSIS 3.0 Cable Modem. I don't know how a person could wrong with owning your own high speed cable modem. You just put in your network setting from the cable company and your good to go. The modem delivers high-speed broadband connectivity to your home and office with download speeds up to 343 Mbps and upload speeds up to 120 Mbps. Channel-bonding technology allows you to get the most out of your existing cable broadband connection. No CD is required for setup. Simply plug the CM3008 Cable Modem into a power source and connect the coaxial cable from your modem to the wall jack. Then connect the Ethernet cable from your Wi-Fi router to the modem. The LEDs on the front of the modem provide a simple way to stay informed about the status of your connection. The CM3008 features the Intel Puma 5 chipset to achieve high-speed downstream and upstream performance.
Date published: 2016-06-13
Rated 5 out of 5 by from Brilliantly Compact DOCSIS3 Cable Modem!!! NB: I received this product gratis in order for me to evaluate and review it. This is a review of the Linksys CM3008 DOCSIS 3.0 Cable Modem with the additional 8x4 Bonded Channels. I replaced a DOCSIS 3.0 modem with 8x4 to test the CM3008. I am very pleasantly surprised! Performance seems the same to perhaps slightly better than my prior modem. What I love most is how compact this is. I have a space problem with a high point where I place my cable modem and router to improve wireless coverage in the areas of my home where I am not cat6 Gb wired (phones, laptops). I has been lovely to have that additional space! It has a very nice display so I can see when the modem channels have bonded and to quickly view the status. Further, now matter how you place the modem, the lights are visible from different configurations - NICE DESIGN, well thought-out! It seems well-ventilated (touch test) with the heat dissipating well (heat- the enemy of long life for electronics). For the technically challenged: Setup is nothing to be concerned about. It is a bit like a wired phone, clicking in a wire between a router/computer and the modem. The other step is attaching the coaxial cable connection - turning the threads until tight. plug in the power, wait until the lights stabilize, signifying the channels have bonded with the ISP, and you have the World at your fingertips! My one disappointment: it has an embedded webpage but it is not available to the user, just the ISP. My prior unit had a webpage that I could access to remotely reboot the unit as well as check on the ISPs configurations - in case tech staff at the ISP muddled the configuration -- it happened to me. I was able to notice that my ISP had finally enabled IPv6 using as well. However, to most users, this is not something they will miss. I hope the designers modify this for those, such as me, who like this option. I highly recommend this little GEM! I have come to like it so much that I do not plan to swap back now that I have evaluated and reviewed. I hope you find the same. Leave it to Linksys. They keep innovating these nice tools! Keep up the great work!
Date published: 2016-06-14
Rated 4 out of 5 by from Small but powerful! Four stars! Setup was easy! Just plug it in, connect the cables and connect! Lightweight, doesn't take up much space. Great reception. Received for free to review product.
Date published: 2016-06-15
Rated 5 out of 5 by from Nice compact and reliable cable modem The Linksys CM3008 cable modem was very easy to set up with my Comcast account. The modem is small and compact. It has performed just as well as my original, more expensive, 8 X 4 DOCSIS 3.0 modem. It has never dropped an internet connection and it boots up much faster than my previous modem. I consider it an excellent choice for a well-priced basic DOCIS 3.0 modem.
Date published: 2016-06-13
Rated 5 out of 5 by from Stop renting your modem! I've been renting a Comcast/Xfinity modem for many years and finally replaced it with Limksys CM3008 DOCSIS 3.0 modem. Installing was very easy, I just unplugged my rental, plugged in the Linksys unit and lastly contacted my ISP customer service to activate the new modem. Took five minutes top and it works as good if not better than the rental - highly recommend!
Date published: 2016-06-20
Rated 5 out of 5 by from Big results from a small package I bought the CM3008 to replace a previous cable modem that had died. I bought it from Walmart at a good price and because of the Linksys name (have always had good products from them). Setup was a breeze and I was surprized at the small footprint of the cable modem. It is also compatible with my ISP (Cox). It has been rock-steady since installation. Good product.
Date published: 2016-11-16
Rated 5 out of 5 by from Works great & simple to install I can finally stop paying the cable company for my modem! The CM3008 works just as well as the one provided by the cable company without the monthly fee. I simply disconnected the old modem, connected the new one, and boom - it activated instantly and I was back online with speeds just as good as the cable company's modem.
Date published: 2016-06-16
Rated 4 out of 5 by from Very Small Device The packaging is very nice with everything inside the box neatly organized. The modem comes with a small, level VI AC-adapter, a CAT 5E Ethernet cable and a quick start guide (but you shouldn't need it). I have Comcast as my service provider, and the modem is on their approved list. The modem is much smaller than the Motorola modem that it replaced at 4.25" by 2.75" and has a Gigabit Ethernet port. After installing the modem and activating it on the Comcast website (make sure you have an old bill handy for your account number), it took what seemed like 10 to 15 minutes to get full connectivity. After that, performance was good. My Internet speeds were not great before, so I didn't expect any improvement with the Linksys modem. I also have VoIP service through Ooma, and that worked as well with the Linksys modem. The website says the modem has a Web-based GUI for management, but I did not test it. FYI, I received a free sample from Linksys in exchange for my feedback.
Date published: 2016-06-23
Rated 3 out of 5 by from Not a bad little modem This little guy came to me and I immediately called my cable company and had it activated. My service is supposed to be 150mb down and 8mb up. Through several download tests, I was able to reach around 100mb down and the full 8mb up. It's docsis 3.0, but lacks in overall speed. I suspect that if you have service that runs at around 50-75mb you'll be just fine, but in markets that offer higher speeds that that, you may want to upgrade to a higher end modem. For streaming services like Netflix, Hulu, HBO Now, and the likes I was pleased. The only time I ever had to buffer was at the beginning of a show or movie. I never had to rebuffer. I also had my PS4 running through and Star Wars Battlefront worked flawlessly. I don't do much online gaming, so you won't get much of a gamers review from me. For what I use the internet for, this modem is satisfactory. It could just use a little more throughput to handle the higher speeds that are entering markets all the time.
Date published: 2016-07-02
Rated 1 out of 5 by from Returned product in 2 weeks due to speed downgrade I returned the product 2 weeks after purchasing it. My speeds initially were 100Mbps(as supported by my comcast provider), in 2 weeks it depreciated down to 20Mbps after it rebooted for some unknown reason. I returned it and purchased another product as rebooting this device did not fix the issue.
Date published: 2016-09-11
Rated 1 out of 5 by from Slowed down wifi speeds Recently purchased to replace Motorola ARRIS Surfboard SB6121 (which is on end of life with Xfinity) and it substantially slowed down my wifi speeds. Previously, with the ARRIS modem, I was getting 100+ mbps when connecting directly, and 80-90 mbps on wifi (using Linksys EA6100 router). After switching to the Linksys CM3008, I was still getting 100+ mbps when connecting directly, but wifi speeds fell to 30-40 mbps. I made no other changes (ie, same router, wifi channel, etc etc). Unfortunately Linksys support was very unhelpful. They said the newly purchased modem is fine, since I am getting the correct speeds out of it when connecting directly. They say the issue must be the Linksys router, and not the modem (even though the only thing changing is the modem and, ironically, the router works just fine when paired with an older Motorola modem). Linksys refused to even provide support/diagnostics without charging me since the Linksys router is beyond its support period. Would not recommend.
Date published: 2017-05-02
Rated 5 out of 5 by from Works perfectly. I've had this for a couple of weeks now. It definitely sped things up versus the modem that Comcast sent. Paired with the WRT-1900ACS, it can't be beat for a home wireless network. Setup was super easy. Another added bonus is that we don't have to pay rental fees for a modem anymore.
Date published: 2016-06-12
Rated 5 out of 5 by from I am very happy The set-up was very easy; even for not so techy me. I did have a time delay problem syncing with Time-Warner but that wasn't a Linksys problem. Bought it for sale price $60. Time-Warner charged $10 a month for their modem, so in six months it will be paid for. Great deal
Date published: 2016-07-23
Rated 5 out of 5 by from Installing Linksys MODEM plus Linksys ROUTER Installing the MODEM CM3008 was very easy and quick with the assistance of the Linksys Tech Support...very helpful, very professional. Installed on my own the Linksys EA6400 ROUTER and that also very quick and easy. Thank you Linksys Tech support Team.
Date published: 2018-05-28
Rated 5 out of 5 by from Plug and Play (after you call your cable company) Once I called comcast to swap out my modem, I had no issues setting it up, pretty much plug and play after that. Its been rock steady ever since. Also keep in mind buying your own modem saves you money each month. Step renting and buy this modem.
Date published: 2016-06-12
Rated 5 out of 5 by from Great Little Cable Modem Setup with my major cable company was fast and easy. Modem worked well with my wireless router. Small form size, nice price, good speed transmission to router, and not much heat generation make this a great product for a moderate-level home network.
Date published: 2017-03-11
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*343 Mbps based on DOCSIS 3.0 throughput. Maximum speed varies depending on the service provided by the cable operator. IPv6 availability is dependent upon your ISP or service provider providing IPv6 capability.
†100/300 Mbps represent the maximum throughput you can achieve with your Internet plan provided by your cable service provider. Actual throughput will be lower than 100/300 Mbps, as this throughput is dependent on your contract with your cable service provider.