Difference on OS X and Windows 7 Wifi reception

[pioneer2000]

Can someone tell me why I can sit in my lounge on my Macbook and when logged into OS X I can get barely any wifi reception from my router but if I login to the bootcamped Windows 7 partition I can get 4 bars of reception.....

 

[paradigm]

Wireless power managment at a guess. Is there any way of controlling wireless power in OS X?