Okay, I downloaded your board's owner's manual from Biostar's web site and it gives pictures of your bios areas. The terminology Biostar uses is unusual but it looks like this would be the adjustment for HT Link speed:
K8<->NB HT Speed
It looks like from post #61 you may have already figured that out.
As I look at your setup and the CPU-z screen shots, I believe the K8<->NB HT Speed is at 4x when on Auto. 200x247=976. I think with your setup the target speed is actually 1000 mhz not 2000 as I said before. Your board seems to express some parameters in half terms and others in double terms when compared to most other motherboard products I have worked with. So with your setup I'm thinking a 1000 HT Link Speed is the same as 2000 on a lot of other motherboards. You could go to 5x but that might create instability and would not give you any better performance. On top of that it looks like you have a bios that will not allow you to manipulate the NB speed apart from the HT Link speed.
I would sit still on what you have now if it is stable. I think you have a nice balance now between CPU speed and memory performance. Run Prime95 and CoreTemp at the same time for at least 1 hr. to check for stability and temps. Don't let your core temps exceed 55-57 C. If they do, you need to look at taking off some vcore and/or reducing CPU overclock speed. If your room temps are hot during the day, test it in the cool of the morning. I like to test when room temps are about 20-21 C or less.
Let us know how it turns out.