Ethernet vs. WI-FI vs. VPN

I was testing the speed of my Comcast cable wondering how much the WI-FI and VPN connection slow me down and the results actually suprised me:

Ethernet directly via cable
15.6 down
6 Mbps up

Ethernet with VPN connected:
15.6 Mbps down
6.6 Mbps up

WIFI (via Apple Airport Base Station 802.1g, not "n" )
16.0 down
5.8 Mbsp

As you can see the speed is the same (+/- small variation), so being tethered on the cable does not help anything really.

http://ukitech.blogspot.com/2009/07/test-your-internet-speed-in-chicago.html

Finally AT&T 3G card:

1.845 Mbps download speed

0.966 Mbps upload speed

As you can see the 3G is NOT a replacement for Cable.