Help with onboard video and mining altcoins with a 7950

Hi,

I was just wondering if anyone has experience using onboard video to run Windows while using an HD7950 to mine altcoins. I haven't been able to use both at the same time. Either cgminer won't recognize the add on card (when I initialize the onboard video) or I initialize the card and the on board chip will not function. Is it possible to free up a few extra hashes by letting my MB run the OS video? Or, more importantly, prevent video glitching while mining without significant loss of hashing power. Right now I have to cut about 20% of the hash rate to run glitch-free.

Also, I ordered a new MB/CPU that will support multi-GPU mining. I read that I may need to build video plugs to prevent the cards from shutting down with no video output. Is that really necessary? Will cards really not function when not attached to a monitor of some sort? Could that be my current problem with both onboard and card video not working at the same time?

Thanks,

Trip