Even though overclocking can increase the tdp of a cpu most 125watt boards can handle a overclock no problem, in ur case make sure u get a decent board as even though it supports 125watts doesnt mean its good for overclocking. As for voltages every cpu is different but being the cpu is stock 3.3ghz it shouldnt be hard to hit 4ghz on 1.3v, i got to 3.8ghz with only 1.375v on my x6 which from stock is a 1ghz OC
http://www.overclock.net/t/946407/amd-motherboards-vrm-info-database - charts of good boards to OC on based on vrm power phase, the charts wont show on my screen not sure y if its just me or the site, so if it doesnt work my bad lol