hi guys
i have a small question
i m trying to mine litecoins atm, i have a sapphire 6950. 
if i say but another gpu , like 7950, i can put it in crossfire with my existing card to get some more hashing power?
I read somehwere that gpus must be same for crossfire.  can i just plug in other gpu and use them both for mining without bridging 'em together?

thanks. 
(also, do threads just gets deleted here?  no lock/why its not there anymore etc.  i think one of mine in off topic section got deleted.  idk how )