[vdb86]

I've done additional tests using iperf.
These are the results using iperf on Raspberry Pi 2 (60 sec, TCP window size: 43.8 KByte (default))

Ethernet: 673 MBytes 94.1 Mbits/sec

Edimax EW-7822UAC 2.4GHz: 431 MBytes 60.2 Mbits/sec

Edimax EW-7822UAC 5GHz: 887 MBytes 124 Mbits/sec

Edimax EW-7811UTC 2.4GHz: 308 MBytes 43.1 Mbits/sec

Edimax EW-7811UTC 5GHz: 829 MBytes 116 Mbits/sec

These are the results using iperf on slow Windows 7 laptop (Intel atom CPU N450, 2GB Ram)(60 sec, TCP window size: 63.0 KByte (default))

Edimax EW-7811UTC 2.4GHz: 266 MBytes 37.1 Mbits/sec

Edimax EW-7811UTC 5GHz: 402 MBytes 56.1 Mbits/sec

Edimax EW-7822UAC 2.4GHz: 364 MBytes 50.9 Mbits/sec

Edimax EW-7822UAC 5GHz: 502 MBytes 70.2 Mbits/sec

This tells me that the drivers are not the ones to blame (at least not 100%), speed depends on the rest of the hardware too, I guess some USB controller and whatever else.