Performance problem with wifi ralink RT3290LE

The first thing I would try is disabling the powersave of the power management.

sudo nano /etc/NetworkManager/conf.d/default-wifi-powersave-on.conf

You will see:

[connection]
wifi.powersave = 3

Change that 3 to a 2

[connection]
wifi.powersave = 2

Tap ctrl+o to overwrite, then the enter key to save the current configuration, then ctrl+x to exit the editor.
Reboot the notebook and test.

The powersave can be a bit overzealous about limiting wifi access in comparison to powerdrain.