yeah, its possible, but it would make as much sence as getting in a wheelchair and rolling down a hill in san francisco in rush hour. the stock heat sink and fan is really good for the amd's, but if you want really good cooling, take a look at these two...(granted as long as you have enough room to put them in your case) ;p
Zalman CNPS9500 LED CPU Cooler
http://xoxide.com/zalman-cnps9500-led-cooler.html
or
Thermalright SI-128 and a Thermaltake Thunderblade Fan.
http://xoxide.com/thermalright-si-128.html
http://xoxide.com/thunderblade4.html
my best friend has the si-128 with the thunderblade and his cpu (x2 4400+) idles at 28c and under full load its like 38. the thing is a beast. also, thermalright gives you a tube of "generic paste" with the heatsink, but dont be fooled. it is some of the best performing paste out there. it is better than the arctic silver 5, and it runs up on the heels of the arctic silver ceramic.