I am running arch linux on my pi.
My wifi adapter:
Edimax Technology Co., Ltd EW-7811Un 802.11n Wireless Adapter [Realtek RTL8188CUS]
On the power front, 12W ipad adapter.
My suspicion was the "power saving feature" of the device. So I created an config file for the module in /etc/modprobe.d/ which disables power saving. It didn't work :(
options 8192cu rtw_power_mgnt=0