I have the following problem on my Lenovo T410 with Ubuntu 12.04: On a certain Wifi, my connection is horribly slow (download speeds of a few kB/s despite the connection being 100/100). For other users of this network, the connection speed is fast. If I boot up my computer in Windows (dual-boot), the connection is fast. My computer with Ubuntu using other Wifi networks: fast.
After searching around here a bit, I found the tip to set modprobe -v rt2800pci nohwcrypt=1, but this did not help. Any other suggestions? Please let me know which logs or outputs you would need.