OP, if you can set rthe mulit to 9.5 then it's an e8500. No, you don't need an extreme edition to change the multi. They all let you adjust the multi downwards. The difference with the extreme edition is it let's you adjust the multi to above the stock value.
Somebody with that gigabyte board, please put the OP out of his misery. He probably has his memory set way out of spec or something.