Because for some reason, using GUIminer lowers my hash rate.  With CG I get 680 per card.  With GUI I get about 667. 

I'm mining Litecoins not BTC, sorry for the confusion.

So for some reason my PC would OC 3 of my 4 cards, all I did was insert the card directly onto my MB and I was able to OC it.  Not sure what that issue was but at least that solved the issue. 

All 4 cards are running fine now and tomorrow I'll start the OC'ing to get the best numbers.

Thanks for the suggestions everyone. 

I have a new setup so far but on my 3rd card which just arrived today from newegg, i'm only getting 75kh/s.  In addition to that, it lowers my first two cards Hash rate to 300 kh/s.  

I have the following setup:

ASRock extreme 4 970 Mobo
8GB Corsair Ram
AMD Sempron single core processor
3 Sapphire 7970 Dual X video cards

Can anyone help me understand why my third card is slowing down my hash rates?

Im using the following in CGMiner

--scrypt --thread-concurrency 8192 -I 13 -w 256 -g 2 --gpu-engine 1019 --gpu-memclock 1496 --shaders 2048

I have all 3 cards on risers.  2 on powered 16x-16x risers and 1 on 1x-16x riser. 

Hi just saw this post.  I have sapphire 7970 dual x video cards.  Currently using guiminer and getting 647kh/s and 622 kh/s out of them. 

Running

Core clock 930
mem clock 1355
voltage 1137

Going to mess around with them this weekend to push 700+ per card.  I have another 2 on the way also.