Almost always, motherboards are backwards compatible, meaning they can slow down to an older CPU.. but never being able to speed up to handle a newer CPU.
Can you post the exact model of the motherboard in question?
If you are talking about your E4300, then yes that motherboard supports it.
Hold on, that link don't work correctly
For some reason there is a space between p5k and ws and its not letting the link work correctly. Just add a space between it when going to it. or go here and punch in the motherboard model.