Test results:
On linux: works perfectly (tested on debian distro 7.)
On 64-bit Windows 8.1: the card is directly recognized as Qualcomm atheros card AR938x. My first instinct was to go download the latest driver from tp-link but it turns out that the card works less well with the latter driver, so back on the driver installed by Windows and the card works as well as on linux.
To conclude: works well for windows but not to touch the pre-installed driver ... the tp-link driver 06/05/2014: less good signal and speed