ASUS RT-AC68P 100% CPU Usage Solved

Recently bought a T-Mobile AC1900 router that is really an Asus RT-AC68U under the badging, and just needs a few firmware “corrections” to get the T-mobile out of it and give you a $37.00 semi-high-end router.

My firmware updates went fine.  I followed the steps and got updated to the latest Merlin build – 384.6.


The UI for the router admin was extremely slow.  Users got kicked off once in a while.  I noticed that CPU Usage of both CPUs were pegged at 95-100% constantly, and my RAM usage was stuck at 50%, which didn’t seem right either.


It took some playing, but I finally found the USB Application menu, which wasn’t intuitive – because I had no USB devices plugged in, so I figured those things would automatically be disabled.  Wrong.

You have to go make sure things like “Enable iTunes Server” and “Enable UPnP Media Server” are turned off if you’re not using them.  It’s not automatic just because nothing is attached.

How to find it: Go to the USB Application item on the left-side nav, then…

And from there, you’ll see this sort-of hidden set of options:

The USB Application “Media Server” settings page in Asus/Merlin firmware v384.6

Once this was disabled, my CPU usage dropped to under 20%, and my ram usage dropped to 25%

This doesn’t affect my regular UPnP settings – that I had to enable to use my Xbox.

By the by, check the other network services linked from the USB Application page to make sure Printer Server, Time Machine, etc. are disabled if you’re not using them.

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