Firstly, and most annoyingly, using a Wii USB LAN adapter actually causes the Wii U to download slower, compared to WiFi. So if you are getting a good WiFi signal, keep using it.
Its likely even an old 802.11g WiFi network will still be faster, as I have yet to see the Wii U do anything close to 802.11n speeds. My guess is it doesn't have any of the fancy features of 802.11n that make it faster, many smartphones have the same problem.
Now, what do you need to do for optimum speeds then?
1) Use a proxy server. To do this you need a PC or Mac to run the proxy server on. You may be able to use one on the Internet but I suspect this will not actually speed anything up, as its not the Internet speed which is the problem, its something to do with how the Wii U is actually downloading the files. To do this lookup the instructions for how to speedup PS3 downloads, its exactly the same method and I already had one setup for my PS Vita, I just used the same settings on the Wii U.
Now, go into the Wii U System Settings, Internet, Connect to the Internet, Connection List.
Click on your connection and then Change Settings. Scroll two pages to the right and choose Proxy Settings, Configure, and input your proxy server details.
2) Grab yourself an external USB HDD, connect it to the Wii U and go to System Settings, Data Management, Format USB Storage Device. This WILL delete everything on the HDD so make sure there is nothing you need on there first. Once you have done this the Wii U will automatically use the HDD for downloads rather than the internal memory.
The only place I have seen this mentioned is in Home menu, Download Management. While a download is running it will say that its downloading to USB Storage.
By doing the above I managed to download the FIFA demo three times faster than before. For the more technical people, my download speeds went from 500-800K/s to 1.75MiB/s over the LAN adapter or up to 2.2MiB/s over WiFi.
The interesting thing about that also is that as I have a full Squid proxy server and did the test several times, those results were the actual MAXIMUM speed the Wii U was able to handle. It was downloading directly from my proxy servers RAM cache not the Internet. So unless they fix the poor LAN adapter speeds, this is pretty much the best speed we can ever expect from Wii U downloads, as its more or less what you would expect from 65Mbit WiFi (WiFi only ever does around 1/3 of the speed its advertised as supporting, due to the complexity of the protocol), which is what the Wii U appears to max out at.
What also doesn't help is that Wii U downloads are split into several parts but only downloaded one at a time, so you get several pauses in the download which also contribute to making the download take longer. It would be nice if Nintendo enabled parallel downloads, even if its only while you are on the home screen and using USB storage.
Installation was also MUCH faster to USB storage. I didn't time it, but at a guess I would say it took under a minute compared to several minutes when using the Wii U internal storage. Nintendo clearly know this as once you have USB storage connected it is used automatically, they do not even bother to ask where you want to download/install save stuff, it just goes on the USB storage. A bit annoying actually as I would rather keep my save data on the internal memory with just games themselves on USB.
With the evidence pointing to the internal memory being really slow, it makes you wonder if Nintendo will actually be able to improve the speed of navigating the OS. It looks like they are going to have to preload everything into that 1GB of RAM if we want to see any improvement.
Edited by Alex Atkin UK, 05 December 2012 - 08:50 PM.