I noticed recently that my upload speeds went from maxing out at 5MB/s (ISP limitation) to an average of 1.9MB/s – no matter which PCs I used and no matter whether they were wired/wirelessly connected. After plugging in my HP Mini direct to the cable modem [and getting max speeds there], I realized the issue was not with my ISP, but with my ASUS RT-N56U Wi-Fi Router.
The issue only recently became evident, as I was always able to get full downloads/uploads before. Seemed odd this would crop up out of the blue like that. But it is what it is, so I ventured to fix it right away.
I attacked the problem by first updating the firmware – 126.96.36.199d was now available at the ASUS support website [ http://usa.asus.com/Networks/Wireless_Routers/RTN56U/#download ] . This made no difference – upload speeds were still limited. I then tried removing any patch cables that led to downstream switches on my network. Again – no difference. I tried linking the router to the modem under a different port and with only my Mini net-book as a wired client PC – no change. I then was curious if the four new entertainment devices [TV, Amplifier & 2 Bluray players] with wireless networking could be causing issues, but after watching the ASUS’ real-time traffic monitoring [nice feature, ASUS!], I saw nothing was really taking up any bandwidth – not a single device at all. I blocked all devices but my testing PC, and still – no change. Nothing I did made ANY difference – UNTIL…
I decided the last thing to do before I returned the ASUS router under warranty was to do a factory reset. I did the reset, and plugged everything back in as it originally was, and the router took me through it’s initial detection and set-up sequence. I set everything back up again [what a pain!] making sure to get my settings exactly as they were before. I tried the speed test, and immediately noticed the change. I once again am getting consistent full upload/download speeds from all tests.
In hindsight, the only ASUS router setting I might have made that could have turned on some sort of internal speed governor was to set my XBOX and PS3 to ‘high priority’ via the client list. If doing so means that the ASUS permanently limits upload speed [by 60%!] for the other ‘NORMAL’ priority clients, then this is a terrible QOS (Quality of Service) solution. That is why I am discounting it as the problem. ASUS has not shown themselves to EVER be of that ‘shotgun’ approach before. Yet, I have to wonder… [leaving that priority setting alone now - just in case!]