Seems to work fine with my 2.4ghz tp-link router with channel width set to auto (and this router isn't draft n, its brand new). I get between 150-300mbps depending on where I am in the house, I don't have any other routers near me (rural area) and my cordless phones are 5.8ghz.
So saying its not possible on 2.4ghz is false. Not always plausible? Yes. But 5ghz isn't always plausible/ideal either. I previously had a dual band cisco router, and 5ghz was so horrible at penetrating through walls that I used 2.4ghz anyway because it gave me better range/performance, and this is a fairly new house with thin walls and no exotic materials.
Well darn, your should sell your Stuff to CISCO, they cant do 2.4 300. You got some time warp router thats bends the laws of physics and beats CISCO's top of the line router.
What brand you got so i can tell CISCO they need to buy them and get out if the Dark Ages.
I still stand by my comments, and you didnt post your router config and just showing a 5GhZ connetion imo, but thats ok, when i get to work tommorow ill make some phone calls and find out one way or the other.