Cooling the Linksys E3000 – Part 2 – Inside the box

After much discussion and feedback regarding my original post “Cooling the Linksys E3000“, and my own curiosity as to why this router got so hot, I decided to press on and look further into it.

I’ve heard rumors that speculate that one of the reasons this router gets so hot is because of an underpowered AC/DC adapter. I generally don’t agree with that and here’s why: The device is hot but the adapter isn’t. In my experience AC/DC adapters which are under-powered will run the adapter hot — as it’s overloaded — and the device won’t function under load, as there’s not enough power to all of the components. In this case, the AC/DC adapter isn’t hardly warm (I just checked mine) and appears to meet the device requirements (12VDC 2A). So I don’t believe the heat issues are related to the adapter. So if the problem isn’t related to the AC/DC adapter, it must be due to lack of adequate cooling. I removed my cooling fan and opened the case. The screws are T10 torx security screws, labeled CR-VT10 in my kit, for the interested. The first thing I noticed after opening the router was that there was plenty of RF shielding and actually a heatsink mounted on one chipset. I decided against removing it as I didn’t have anything to replace it with if the adhesive didn’t re-stick. I then set up a moderate test to keep the router busy while I probed the uncovered chips with an infrared thermometer.
Here is my setup:

Wired:

  • Port 1: Wii streaming Netflix
  • Port 2: Gigabit NAS

Wireless:

  • 5Ghz Wireless-N device (300Mb/s) copying a large amount of data from the NAS

As you can see I’m far from pushing the router to it’s limits but I am certainly keeping it moderately busy. I ran this level of network activity for about 5 minutes then started taking temps. I found two chips that had operational temperatures above 45C:

The first was the Broadcom BCM4322KFBG controller at 62.8C

bcm4322kfbg

This is a product of the Broadcom BCM4322 family of 802.11n controllers. Here’s the datasheet.

The second was the Winbond W9751G6JB-3 DRAM chip at 47.6C. This is a 512Mb DDR2 SDRAM chip.

w9751g6jb-3

It seems to me now that the Broadcom chips are almost solely responsible for much of the overheating issues in this router family, with the DRAM chip potentially taking some of the blame as well. I’m planning on ordering a set of Zalman VGA heatsinks and put one of them on each of these chips. It should help a lot, especially with the fan on the bottom to keep the air moving.

As the nature of heatsinks is to transfer the heat from the chipset to the air, I’m sure that I’ll notice a slight increase in the temperature of the router’s case itself, but the resulting heat transfer should be improved with the aid of the fan, and I’m sure I’ll be able to expect my router to live a much longer life.

If anyone has any thoughts to share on this please do so in the comments below. Thank you!

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  1. #1 by NMI on June 25, 2011 - 12:32 pm

    Awesome! Genius even. If I ever get the money to buy an extra one, I want to get spare, working PS3 and see why it heats up as much as it seems to.

    • #2 by Mike on June 25, 2011 - 12:36 pm

      Let me know if you want any help with that :)

  2. #3 by Taylor on October 17, 2011 - 11:42 am

    did you ever put in the VGA heat sinks?

    • #4 by Mike on October 17, 2011 - 9:39 pm

      Yes I did. I reassembled the unit afterwards and haven’t seen any noticeable performance issues. It’s been quite stable since.

  3. #5 by Tony on January 24, 2012 - 9:37 am

    I am planning on buying a couple of used Linksys E3000, load DD-WRT v24 Mega load on it, and use it for VPN PPTP for my small business as well as my home. After reading both your articles on cooling issues and resolution, I have decided to follow your first article and install a cooling fan and rubber feet once I receive my router.

    Question: is the outside cooling fan just enough to keep it cool or do you still recommend opening the case and install 2 small heat sink on the two chips as well as installing the outside fan? Thanks for the article and your opinion.

    • #6 by Mike on January 24, 2012 - 9:57 am

      I think the outside fan is sufficient. I went the heatsink route just to give a little extra cooling.

  4. #7 by John on February 15, 2012 - 12:56 pm

    Nice article – I’m going to give a USB powered notebook cooler a try for my setup. Just snagged one for cheap off woot today: http://www.woot.com/blog/post/microsoft-notebook-cooling-base-1

    This one includes a fold-able stand so I can prop it up for better airflow.

    • #8 by Mike Beach on February 21, 2012 - 8:16 am

      That’s a great idea! A little bulky, but will work just the same.

    • #9 by Anthony on February 21, 2012 - 8:19 am

      Take a picture and post it here so we can see how it looks like. I agree with Mike, great idea.

      • #10 by Mike Beach on February 21, 2012 - 8:21 am

        Yes please! I would enjoy seeing it as well :)

  5. #11 by David on April 20, 2012 - 2:26 am

    Hey could you tell me how did you do to disassembly this router E3000, because I can see just 4 black little screws and nothing more out there and it is not openning easily. Is there any other screw that I am not seeing or any plastic lock around there or in the device? I would be really thankful due to Im trying to put some heatsinks as you did.

    • #12 by Mike Beach on April 20, 2012 - 5:34 am

      After you take the 4 screws out, you have to carefully pry the case apart along the sides; the rest of the case is just held together with clips. It’s easier to start with the front and move along the sides to the back.

  6. #13 by Ad on August 19, 2012 - 6:47 am

    With DD-WRT you can adjust the RF transmit power. Reducing that power lowers the temperature, and increases the wifi bitrate. So it must be the overheated Broadcom chip causing the performance loss, not the DRAM chip.

  7. #14 by axehandle on August 29, 2012 - 7:37 pm

    Is there a way to control the USB port from the router? I’d like to be able to turn the fan on and off programmatically. It’s silly to have it running all day long, even when the router isn’t working up a sweat. I suppose one could put a temperature-controlled switch in-line, as well. Any thoughts?

    • #15 by fuzz on April 28, 2013 - 9:29 am

      If you load DD-WRT on the router (and I think maybe with the stock firmware, but I doubt it) you can control the on/off of the USB port from the web interface. It’s just a small radio button toggle on and off. Switching this option makes/breaks power delivered through the port, so effectively you can use this to control the fan.