What processor are you using?
Anything above Athlon 64 is 64Bit compatible, "Athlon 64X2, Athlon 64FX, Athlon 64" since these are the compatible processors of your Mobo, I guess, It is 64Bit compatible.
If you want more details for your processor, then try using CPU-Z
from here
http://www.cpuid.com/softwares/cpu-z.html
and give me the Processor Name, I'll tell you whether or not it's 64Bit compatible.