I have a 7950 and I just added a 7970 to my computer.  Is there a way to run 2 instances of cgminer so I can use different workers and different bin files?  I would think my 7970 would need to use a different bin file to get the most performance.  I guess I just need help figuring out how to set it up.  When I launched it right away both cards started mining, but I did notice my 7950 was mining a little slower than it did as a single card.  Is that normal?

EDIT:
The khash is only a couple lower, not a big deal.  I do need to figure out what to do though.  After I overclocked the 7970 it is still going slower than the 7950, so I am obviously not doing something right.

EDIT:
Someone helped me.  The command is --device 0 or --device 1 etc.

EDIT:
Still getting very slow speeds.  Only about 450khash no mater what I do.  I did see that trixx reports that card is running @ x8 1.1 - don't know if that matters for LTC.

I tried removing and re-installing drivers, but that didn't make a difference.

EDIT:

Following this guide: https://bitcointalk.org/index.php?topic=28402.msg1635964#msg1635964

After I delete bins and enter: setx GPU_MAX_ALLOC_PERCENT 100
Then simply run: cgminer --scrypt -I 13 --device 0 -o stratum+tcp://stratum.give-me-ltc.com:3333 -u myuser -p mypassword
I get about 550khash.  Then ANY changes I try to make (such as --worksize 256 or whatever) all give me lower speeds.  Here is what the bin file name is that it generated: scrypt130302Tahitiglg2tc22400w64l4.bin
Again, this is for my 7970.