Your fix hasn't worked for me.
Using the downloaded programme, Namebench, you can find the best DNS settings and, in my case, turning off HTTP Proxy. gives me the fastest speeds D/L 40.32mbps, U/L 17.16mbps
So as you see with my phone I am finding the speed test results very good, but buffering of data such as video, ridiculously slow.
I run my iPod touch against the iPhone 5 in downloading and running the same short video, at the same time and find the video downloads, runs and finishes on the iPod touch whilst the iPhone is failing to buffer enough data to run the video without stopping and waiting for the next batch of data. Hopeless... it taking over 4 minutes to run a video 93seconds long.
I've heard that Apple are beginning to assemble their products in the US, is this correct? I noticed with a friend's iPhone 4s, when it was opened to
see why the microphone wasn't working, that part of the assembly was incomplete! Is poor assembly the issue? It would support those who believe the issues
with the iPhone 5 are hardware not software related and why some people are not experiencing any problems at all.
To summarise, I don't think the problem is wifi speed but with buffering and I suspect poor quality control in the factory where the phone are being assembled.