Overclocking the WRT54GL

One of the favourite subjects that keeps coming up in the forums is that of overclocking the WRT54GL (and now also the TM). Specifically, what is the maximum safe speed, does it overheat your router, and what is the point anyway?

Let's start with the last question. If you have so much traffic that your router is struggling, then quite obviously having more speed would help. Such a situation is common these days when many people have more than 20Mbps internet connection.

So why do *I* overclock, because I have only quite feeble 5Mbps ADSL links?

The answer is simple.

Overclock by 25% and the speed of most things increases by 25%. That is actually quite noticeable. If you do get everything working properly, and as fast as you can possibly make it (this includes modem/MTU/router/ethernet cards/switches/PC/Sufficient Memory/Decent Web Browser/Half-open Connection Limits/Good Operating System etc..) then the reward is an almost instant response to the web GUI from Tomato. Plus, faster response from web browsers, more throughput for your P2P, lower latency, better gaming, etc.

Individually, a 25% increase doesn't seem like so much. Now add up the effects of 25% increases in all of the above - and you will be amazed how crap your internet was before you began. Does downloading a movie in 3 hours as opposed to 4 hours make sense? That's what you can get by overclocking, sometimes more. Pay attention to all of the other things I mentioned? You just might find that movie arrives in 2 hours. I really want to emphasize this - every customer who has ever seen my internet access working has said it's much faster than theirs. Yet I use the same router that they do! The usual reason is either they are using laptops or PC's which are poorly set up or have insufficient memory.

25% extra speed is normally easy to achieve with the WRT54GL running at 250MHz. At that speed, most GL's are stable (I have only ever had one that wouldn't overclock at 250Mhz). And yes, it's very noticeable. The GL is way ahead on speed of the ASUS WL500gP v2's which I also use, even at 200MHz. Subjectively, the 500 "feels" SLUGGISH.

The maximum "safe" speed is normally 250MHz. There is a very small possibility that YOUR router may not overclock to 250. And I mean small. Actually I only say this to cover my ass. But it's up to you to decide whether to do it or not. Feedback from those who have changed the cfe to allow higher clocks indicates that the majority of CPU's will actually run at 275MHz. The data sheet for the BCM5352 seems to have disappeared from public view these days - but a short product description that is available shows that the design limit for this precesor was 264MHz. So actually, we aren't overclocking it at all!

I have no idea where it started, but there are hundreds of posts in the forums warning people about "overclocking", saying it will trash your router. That is complete nonsense and I really wish people would not talk such utter crap. Just stick to a known working clock frequency, and do not try to flash an odd number "off the top of your head". Usually the next available frequency is used, but just in case it isn't - don't do it.


NB There is a known problem with selecting 215MHz on some models which will brick your router (which is odd because usually selecting an invalid frequency will just select the nearest lower value from those listed). USE 216 !!

These are the valid clock frequencies for the WRT54GL - 183, 188, 197, 200, 206, 212, 216, 217, 225, 238, 240, 250.

Note that although 264Mhz is the design limit for this processor, this is not one of the clock frequencies supported.

*** [For the ASUS RT, the list is very long. Most RT-N16's will not run at 532MHz, and Broadcom, the makers of the chip, now state the maximum operating frequency is 480MHz. I find mine all run OK at 500MHz. So a nice selection would be, say, 266, 300, 354, 400, 453, 480, 500. And 532 may be enabled in the future]

[Versions of Toastman firmware after September 2010 will have a safe frequency selection drop-down list, which hopefully will reduce the number of bricks caused by entering incorrect frequencies.]

It is *possible* to go above 250 but then you really do start to tread on thin ice. Firstly, software modifications are usually necessary to enable any support for higher clock speeds. Then as you approach the true limit (said to be typically around 270-300MHz) the chip may well need extra cooling. There's a real danger of bricking the router irrecoverably. In fact 250MHz is the fastest overclock that can be achieved without modification of the table in the cfe. Anything higher than this, will show a setting corresponding to what you selected, but the reality is that it doesn't really change at all. Those interested in clocking higher than 250Mhz, take a look at this link:


So, at 250MHz, does it overheat? Does it explode? Does it somehow end up with a shortened life? No, the evidence is that it does not. Let me expand on this. I live in a country where the temperature is always over 30 degrees and often 40+ degrees. Because I have many routers running in many remote locations it is very important to me that they are stable. I've used these routers under full load over more than three years in full sun in enclosed cases with no ventilation, fans, or additional heatsinks. They don't overheat and there's really no need to add a heat sink, though if it makes you feel better and you know what you are doing, there's no harm in it. Adding fans is really quite pointless. Adding a fan means having holes in the enclosure, access to insects and lizards, problems with dust and dirt, and the need for maintenance on the fan itself. Kinda like shooting yourself in the foot.

However, there are a lot of zany people out there who want you to believe your 30 dollar router is some kind of advanced supercomputer and needs to be run by a nuclear reactor and cooled with liquid nitrogen One guy even has heaters and coolers and all manner of temperature sensors on his externally mounted WRT54GL. Another idiot has an Arctic PC CPU cooler towering out of a huge hole cut in the case. If you really like to impress your friends I can recommend this fan:


especially if you strap one to each ear.

Well, it's a free world, and if you have nothing better to do but to make a prat out of yourself …

Now the same old people having problems with their RT-N16's firmware are busily spreading the same old "router is overheating" crap.



There have been many posts in which people have claimed that their router must be overheating because the router has "slowed down" and an instant cure has been to add a heatsink when all was magically restored to normal. Let me just point out right now that this is also absolute crap. Overheating microprocessors do NOT slow down gracefully when they overheat. They fail to work properly. That results in:

system crashes
random lockups
memory errors
application errors

The exception to this is when the manufacturer of the particular microprocessor has deliberately implemented some scheme to protect the chip. This is for example done by Intel in their PC processors. They have onboard temperature monitoring and onboard circuitry so that when a threshold is reached (and also please note that this is at around 90 - 100 degrees C) - they reduce their clock speed.

As the microprocessors used in SOHO routers most definitely do not have this kind of protection, it is not possible that a router has "slowed down" due to overheating. Be careful what you believe when reading forum posts. Most of these claims are just assumptions by non-technical people who read it on a forum …. and here we are back at the beginning again …… Please don't accept everything you read on forums as gospel !

There are also many posts like this one:

What I have read, however, is better signal strength and larger range using the wireless connection while overclocked.

Now, how the f*** is increasing the processor clock speed supposed to make any difference to how much power the transmitter puts out? This kind of crap *really* makes my blood boil.

Rant over …


November 24 2009

Today is 1 year since I installed around 200 more routers/AP's in another four condo blocks. All running 250MHz at 150mW, all in enclosed boxes with PSU, no ventilation, no heatsinks, no fans, no liquid nitrogen tanks or cooling towers, about 20 of them are in direct tropical sunlight, and NOT A SINGLE FAILURE. I haven't even had a single electrolytic capacitor failure. I now have about 300-350 routers and AP's (December 2009) - many of them have been up for over 2 years.

October 10th 2010

More than one year has passed with not a single failure of the existing WRT54GL's, and a lot more now pressed into service, total now is around 400. Plus several AUSUS WL-500gP and RT-N16's, which I now use for the main routers.

The two WRT54GL's that I have bricked myself due to experiments that went wrong have been successfully recovered by JTAG. That is a 100% success rate with a large number of quite cheap SOHO routers - so I take my hat off to Linksys!

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