Asus Z68 Motherboard

Ready to build a new PC with SRT capability, which is why I am thinking of a Z68 board from Asus. I been reading some rumbling that if you disabled the on-board GPU, that graphics performance with the PCI graphics module is somewhat compromised. Any truth, because I primarily intend to do photo editing (heavy duty) using Photoshop CS5, Lightroom and a myriad of other packages and not all graphics modules play nice with these packages. Any thoughts????

Thanks,
Dan