Take the crossfire bridge off unless you use it for gaming. It hurts your hashrate.

i did some testing and doesn't get lower, always 550kh/s are u sure it hurts the hashrate?

No, it doesn't affect hashrate. Most people who say so have never actually done any testing for themselves.

I have done testing, and it did effect hashrate on my cards. I don't have them anymore, so I can't give details other than they were 5870s.