I have followed this guide twice.
Some time ago I installed Lucid and followd this guide.
Everything worked perfectly! I could connect to my WPA2 secured SSID and got a link speed of ~270mbps.
I could transfer files at ~9-11 MB/s from my Win7 desktop.

A week ago I reinstalled Lucid on the same computer but on a larger, newer, faster SATA drive.

I followed this guide once more but now my transfer speeds max out at ~2.5 MB/s
Link speed is still at ~270mbps but signal drops to low when transferring files (only the "dot" and one "bar" in NM-applet).

I reconnected the old SATA drive and transfered some files and behold! The old install still reaches speeds up to 11-12 MB/s!
Signal is max in nm-applet, sometimes drops to max -1 "bar".
The average transfer speed is ~9.3 MB/s on the old install and in the new install ~2.5 MB/s, peak 4 MB/s

I can't figure out what could be the difference between theese two installs, could anyone please point me in the right direction or give some tips on how to troubleshoot this?