o shit!  illuminate pyramid stuff

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 )

i may know nothing on politics, too ignorant maybe but i think this changes nothing.  only thing that changes is that instead of this party, that party is in power, aftermath is probably gonna be the same.  same system same economy etc. oh ya and scams