Cisco/Linksys E4200 overclocked to 532 MHz

How To: Overclock a Cisco/Linksys E4200 Router running DD-WRT 42

Cisco/Linksys E4200 overclocked to 532 MHz

UPDATE: Newer versions of the DD-WRT firmware now include a web-based option for selecting your overclock speed, if it’s supported on your device. You can still follow these steps to overclock (and I recommend you continue reading so you understand what you’re doing), but now you can access overlocking on the Administration/Management tab.

Overclocking means forcing a device’s CPU to run at a faster clock speed than was set by the manufacturer. Overclocking is not for the casual user. The idea is that with a faster clock speed, a CPU can process instructions at a faster rate, providing a faster overall experience when using the device. The cost of overclocking, however, is increased heat. And heat is the mortal enemy of all electronics.

The Cisco/Linksys E4200 (version 1) router has a Broadcom BCM4716 CPU, which runs at a default clock speed of 480MHz. I’ve been able to reliably overclock it to 532 MHz, and I’m sure there are some crazies out there who’ve pushed it even further.

However, before I proceed with explaining how to overlock a Linksys E4200 v1 router, I need to make something crystal clear: overclocking is dangerous. If you mistype any part of the overclocking commands below, you can brick your router. If you choose an overclock value that is incompatible with your hardware, you can brick your router. Overclocking will increase the heat inside your router, and can potentially melt stuff, and can brick your router. If anything goes wrong, you can brick your router. Bottom line? Don’t do this unless you can live with the risk of possibly bricking your router.

These instructions are only for the E4200 v1, as different clock speeds are compatible with different units. I haven’t tested overclocking on any other routers. I don’t know what overclock settings will work with other routers, so please don’t ask.

I will not answer any overclocking questions in the comments below or via email. Please allow me to repeat that.

I will not answer any overclocking questions in the comments or via email.

Feel free to comment below with a “Yay! It worked!” or “Crap! I bricked my router, but I’m not mad at you, Steve, because you totally warned me and I have nobody to blame but myself!” or even share other tips or input. But unlike my other blog posts, if an overclocking question appears in the comments below, I’ll either ignore it or reply “See above.” If I get an email question related to overclocking a router, I’ll simply delete it without replying. There will be no exceptions. I’m not trying to be a jerk, I’m just trying to clearly state that you are 100% on your own if you proceed.

The very brief blurb on the DD-WRT overclocking wiki page says:


Have I scared you off yet? OK, if not, then I’ll admit that the three E4200 routers I have overclocked @ 532 MHz (they normally run @ 480 MHz) are running great. That’s not a huge clock speed increase, so I’m pretty comfortable with it. I haven’t noticed any temperature issues, but that doesn’t mean you won’t. I haven’t noticed any reliability issues, but that also doesn’t mean that you won’t. Again, if you choose to type the following lines to overclock your E4200, you do so at your own risk.

First, you’ll need to have DD-WRT running on your E4200. Follow these instructions to flash DD-WRT on your router, if you haven’t already done so. Although, if you’re not already running DD-WRT or some other third-party firmware on your router, you should probably ask yourself if overclocking is really for you. I’d recommend experimenting with hacked firmware first, before moving on to this more advanced stuff.

Now for the risky part. SSH in to your router (if you don’t know how to do this, stop now… you really shouldn’t be overclocking).

Once in the shell, type the following three commands to overclock the E4200 v1’s Broadcom BCM4716 CPU @ 532MHz:

nvram set clkfreq=532,266,133
nvram commit

Cross your fingers and pray while your router reboots. If it comes back from the reboot, party on! Check the CPU section of the Status:Router tab to verify that your CPU Clock value reads “532 Mhz.” If so, welcome to the Overclock Club. 🙂

If the router doesn’t come back from the reboot, I’m sorry. You have my sympathy. Try a hard reset of your router before you panic. Beyond that, I really can’t help you. Google, the DD-WRT forums, and the search term “serial cable” are your friends. Good luck.

Checking Your Temps

As I said before, heat is the sworn enemy of electronics, so if you’re overclocking, it’s a good idea to keep an eye on the temperatures inside your E4200. The following commands will return the temperatures of your respective wireless antennas. You can paste these on the command line in the shell, or in the Commands window of the GUI.

(Temps are now also available in the Status/Router GUI tab on newer firmware versions.)

For eth1 (2.5GHz antenna) temperature in Celsius:

echo eth1=$((`wl -i eth1 phy_tempsense|awk {' print $1 '}`/2+20))C

For eth2 (5GHz antenna) temperature in Celsius:

echo eth2=$((`wl -i eth2 phy_tempsense|awk {' print $1 '}`/2+20))C

If you want to display in Fahrenheit, you’ll need a two-line command to do the additional converstion:

For eth1 (2.5GHz antenna) temperature in Fahrenheit:

eth1=$((`wl -i eth1 phy_tempsense|awk {' print $1 '}`/2+20))
echo $((eth1*9/5+32))F

For eth2 (5GHz antenna) temperature in Fahrenheit:

eth2=$((`wl -i eth2 phy_tempsense|awk {' print $1 '}`/2+20))
echo $((eth2*9/5+32))F

Going Back to Stock

Even if the overclock was successful, you may have a reason return to the original clock speed for some reason. Maybe your router is overheating and you want to change things back until you can figure out a way to cool it better. Or maybe you want to revert to the original clock speed for some baseline benchmarks. Or MAYBE YOU JUST CAN’T HANDLE THE SPEED, BABY! Whatever your reasons, by examining the command you used above to overclock to 532 MHz, you may notice something mathematically interesting about the three numbers we used. See it? (Hint: if you can divide by 2, you’re “half-way” there… har, har.)

So, if you can remember the default clock speed for this router as mentioned in the 2nd paragraph of this post (fine… I’ll save you the scroll up — it’s 480 MHz), and doing some simple math, you can probably guess the command that will put things back to normal. Take the stock clock speed of 480, cut it in half (240), then cut that in half again (120) and you’re ready to go. Type this from the terminal:

nvram set clkfreq=480,240,120
nvram commit

As before, cross your fingers and think positive thoughts while your router reboots. After it comes back from the reboot, check the CPU section of the Status:Router tab to verify that your CPU Clock value is back to “480 Mhz.” Enjoy your slower clock speed! 🙂

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  • Doug

    Hello Steve,
    I recently picked up one of these routers and I wanted to say thank you for a good, and detailed write up. I don’t have much experience in flashing, modifying routers but I have done plenty of Android phones and have overclocked / built computers as well. I went with build 20801 per your recommendation in the DD-WRT forum, and all your settings here. I even overclocked as well. Everything working well, and this is ANOTHER thing for me to tinker with. Thank you again!

  • Nef

    What made you pick 532 Mhz? Why not 500, or did you work up to that #?

    • Hey, Nef. There have been a few guys messing with different clock speeds in the DD-WRT forums, and that seems to be the most stable.

      • slor

        Isn’t that the “normal” speed for the particular MIPS 74K/BCM4716 chip setup that’s in the E4200? My understanding is that Cisco actually released the router with the CPU underclocked at a couple steps below full speed.

        • Hi, James. That’s news to me if that’s the case, but I don’t have any data on hand to know one way or the other. All I know is the 480MHz is the default speed of the proc as shipped by Cisco, and that according to Broadcom, the “native” speed of that chip is listed at 300Mhz.

          But regardless, I’ve been able to run it at 532MHz without problems.

          • slor

            I’m not 100% sure on it either. I remember reading a post to that effect somewhere that I can’t currently find to reference. One other hit that led me to believe it, though, is this datasheet:
            A few weird things though:
            – I can’t find this doc anywhere on Broadcom’s sites.
            – Firmware on the E4200 currently reports a BCM4716, but it also reports 16 GPIO pins, which the doc disagrees with.
            – The DD-WRT site says it uses the BCM4718 (what does your firmware report?), which is noted in the doc as supporting up to 533 MHz.
            – My router at least only has one USB port on it, while the doc indicates the 4718 should have 2.
            Disclaimer to everything above – I haven’t opened up my router to verify pin count, USB hosts, etc.

          • slor

            One update it may be this link for a similar config in an Asus router that led me to believe the normal clock for the 4716 is 533:
            Like you, my E4200 seems to be running great that that speed.

  • I know you probably won’t answer and I doubt I will try this because I’m quite happy with what I have from my E4200… but I’m very curious about what advantages you think you’re getting from overclocking what is already a very fast CPU, especially by what seems like a relatively small amount?

    • Hi, Monlezup. It’s not a “HELP! I overclocked my router and now it’s hosed!” question, so I’m happy to reply. 🙂

      I think you’re right – the speed increases are likely negligible… if any. Since I’m now running the Mega build on a couple of my routers, it’s possible that those processes run faster, but I doubt I was hitting the processing limits of the chip at the previous clock speed.

      Which leaves the primary benefit of overclocking as the “geek awesomeness” factor. Because overclocking impresses chicks. 😉

    • Yes, it runs the processes faster.

      But these days, the main reason to overclock (at least for me) is because of my broadband 150/65. TomatoUSB and DD-WRT both have issues with high bandwidth. Under DD-WRT, I was only able to manage 75/35 on this router. With TomatoUSB, I see 90/45 (this is through dozens of tests over several days each).

      When overclocking my E4200, I can now see 105/55. Still not quite my 150/65 pipe, but closer.

      As a comparison, under the stock Cisco firmware, I see a rock solid 165/70 on my 160/65 pipe. It’s these custom firmwares that are slow.

      There’s a proprietary Broadcom CTF mod that increases the throughput on the stock firmware, and the TomatoUSB guys have been trying to get it to work (it’s unstable for me with Shibby’s v120 build of TomatoUSB).

      You can read more about the limitations of these custom firmwares here:

  • hid3

    What tempertatures are you running on overclocked devices?
    My temperatures at 480 Mhz in Celsius are 56*C for eth1 and 50*C for eth2. 1-2 Wifi clients not doing much traffic. Ambient room temperature around 22*C.


    • I’m at 47C for eth2 (I have eth1 turned off).

      • hid3

        I’ve also overclocked the router to 532 MHz. I’ll let it run for a few days and observe temperatures.
        Some offtopic question: I’m really new to routers and dd-wrt stuff. I think it would be really nice to monitor some enviroment variables via SNMP (e.g. CPU utilisation, anthenna temperatures, connected client count, etc…). Any ideas is some kind of SNMP exist for dd-wrt and if it’s possible to monitor those values?

        BTW. I’ve read your post about flashing the e4200 with dd-wrt firmware. It’s actually what I followed. I plan on following the tune-up tips too but before that I need to do some testing of ‘stock’ settings. Keep posting! And don’t forget to keep us informed about known/recommended ‘stable’ dd-wrt builds!

        All the best!

        • Yes – there is an SNMP service that runs in DD-WRT, but I haven’t messed with it that much. Your best bet is to check out the DD-WRT forums for a list of the OIDs. Come back and let me know how it goes!

          • hid3

            56 *C and 51 *C after overclocking and running for two weeks. Several WiFi clients, but not doing much stuff. Great!

          • Nice!

  • Bryan

    Is there any way revert the overclock settings? I am having concerns with the temps of the Router and i have read that by turning off the lights in the back you can loose some degrees that way.

    • WHAT???? You want to go BACK? Hehe – actually, that’s a great question. I’ve updated the article and added a new section at the bottom that explains how to return to the stock settings. Give it a go!

      • Also, 500 MHz should also work. You can take a crack at 500/250/125 and see if your overheating problem gets better.

        • Bryan

          Actually 59C high for this router? Because my router has always ran at high temperatures and I am trying to figure out if this is normal?

          • That does seem kind of hot. Mine runs at 48C with no additional cooling.

          • Steve: Is this at room temperature? Mine work at 60C and no overclock. It is in a poorly ventilated closet though with other electronics.

            I guess I can run it in another place for a little while but I don’t have another router at the moment.


          • Yes – mine’s at room temperature in the basement (temp around the router is 75F).

          • what antenna were you reading from?

          • Both read the same.

          • interesting, my 5Ghz is always 6-8ºC cooler, it might be like for some dusting.

    • Matt

      My radios are running quite hot without overclocking the CPU.
      2.4 – 66C
      5 – 56C

      How do you go about turning the lights off on the E4200?

      • Rob

        As for the main ‘Cisco’ light, you can do: gpio enable 5

  • Mike

    Thanks for doing these blogs on this router, I have found them very helpful. I have previously been on only BrainSlayer builds because I didnt know there were other available. I will be moving over to a Fractal build soon and giving your recommendations a try. I am eager to try stuff out and also do some overclocking because I seem to have hit a serious limit on my router’s ability. My friends and I have been playing a game called Sins of a Solar Empire lately over LAN and after 1/3 of the way into the co-op multiplayer game we have LAN pings approaching the 100’s and the game tends to get pretty laggy. Part of that is our CPU usage too since the game engine is only single threaded, but with some wireshark data we found that a single gaming sessions sent out millions of packets and the traffic sent out of just one of the computers (not the host either) was close to 2.3GB of data! Hopefully this overclocking will give us some better LAN performance in our game 🙂

    • Hi, Mike. Hopefully these settings will help! Please come back and let me know once you test them out!

  • FYI: I can confirm that over clocking also works for Netgear WNDR4000 running DD-WRT v24-sp2 (08/19/13) mega (SVN revision 22208), dd-wrt.v24-22208_NEWD-2_K2.6_mega-nv64k.bin as it has exactly the same chip as the E4200.

  • You’re awesome! I use to my e4200 as a repeater and I cant believe how much of a difference overclocking made. My set up uses eth1 in repeater mode and eth2 in AP mode. Normally when I’d look at the wireless packet info for eth1 I’d have about 10% error from the RX packets to the TX packets and by the time that data got to the other radio, I’d lose nearly 20-25%. For the past 2 years I’ve just accepted this as normal but after overclocking, the packet info for both radios are also identical so there’s virtually no loss. Everything that comes in goes out. Also, after using your settings, my speedtest results have doubled. Thanks!

  • Kyle

    The same command worked on overclocking my WNDR3400v1 to 532 Mhz. It has the same BCM4716v1 chipset as the E4200v1. Which is still 100% stable and cool. With that being said, I’m only running one channel, but with two, the temp goes up substantially. So I don’t suggest OC in dual channel mode.

  • Oscar

    Hi Steve,
    I recently picked up E4200 and I wanted to say thank you for a good and detailed Setup. I found many of your settings are onces I already use but I was able to increase my Wi-Fi throughput by following your instructions and implementing some of the changes you suggested and I didn’t have. I just Noticed that the new “DD-WRT v24-sp2 (03/05/15) mega – build 26446” has an overclock dropdown menu that will allow you to over and under-clock the CPU trough the GUI and eliminating a typo risk. It is found under the Administrator Tab > Management > Overclocking. With the options of 300, 333, 400, 485, 500 & 533Hhz.

    Thank you once again.

    • Thanks, Oscar! I’ll update this article to mention that it’s much easier to do now with the drop down. 🙂

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