You didnt say what OS you are running so none of this may be useful to you. XP is known to be not optimised for dual core cpu's and there is a patch from MS for this. It states in the patch that its for game performance but maybe it helps for other things as well.

https://support.microsoft.com/kb/909944/

AMD also have a seperate utility available called the dual core optimizer which may or may not make a difference.

https://www.amd.com/us-en/Processors/..._13118,00.html

Hope some of this helps.