Hmm. When I plug the Air and Mini into my router (instead of connecting them directly with an ethernet cable), the file transfer is about 10 times slower (7 minutes for my 5Gb folder, instead of 50 seconds).
(I'm based in the UK, and using BT Infinity broadband with their supplied HomeHub router).
So I think I'll stick with the ethernet cable connected directly for file transfers, and for internet I'll use both the Mini and the Air with wifi (I consistently get 36 mbps down, 8 mbps up with wifi - same as with wired).
ahhh the joys of wireless.
I live in Howell , New Jersey, USA .
There are 4 military bases within 35 miles of my home.
When they test out their toys "wireless is dropout"
The worst toy they have is this
http://www.defenseindustrydaily.com/return-of-the-navy-blimps-03093/
http://en.wikipedia.org/wiki/JB_MDL_Lakehurst
http://www.navytimes.com/news/2011/10/gannett-navy-after-50-years-airship-program-resumes-102711/
The lakehurst , NJ , USA base is the site of the Hindenburg disaster it is about 15 miles from my house.
They new helium blimps can stay up in the air for weeks on end. They are low cost , due to low fuel use , flying radar/jamming ships
When they are overhead in my area and sometimes it is overhead for hours it is pure death to wireless.
Therefore my house is all ethernet. My area must be one of the worst places in the USA for wireless due to these blimps being so nearby.
Point is I am not surprised that your wireless can be 7x slower then hard wired.
BTW I have 2x 8 port switches.
http://www.newegg.com/Product/Product.aspx?Item=N82E16833127325
and I have this router
http://www.newegg.com/Product/Product.aspx?Item=N82E16833127215 and I only use the wired part of the router.
cable modem (To) d-link router (To);
[1] synology nas
[2] 8 port switch=== pcs and macs I use 5 of the 7. only 7 since one of the 8 is the input
[3] 8 port switch === pcs and macs I use 5 of the 7 . ^^^^^ see above^^^^^^
[4] empty i could add a nas or a switch
I have more then enough this way.