PLEASE goodsir!, You will NOT regret using CGminer!!!, I procrastinated from using it for MONTHS, And to this day i regret all those days that i wasted staying with GUIminer, Trust me dude, CGminer is DEFINITLY what you want Use that, Or Since you have a 7970 Diablo Miner,
CGMiner!!
CGMiner!!
CGMiner!!
CGMiner!!
It will pick all the settings and do everything for you once you get it running!, Seriously! Use it!
Please note your mileage may vary. With my 5870s, phoenix through guiminer gives a higher hash rate and lower temperatures. With my 7970 however, I found cgminer to be best.