I thought you would as a designer. I was thinking for quite a while about getting it but I found my mystic case and haven't looked back
your cpu will be better for cad as games don't use multi-threading yet so cad will utilise the four cores more effectively. The motherboard is because Is because it is designed for extremely high performance so I thought it would again be more suited for the quadro, the ram and the cpu. The p5b is a good board for overclocking as it is hence why I chose it for your gaming rig some other good boards are:
asus p5n series
gigabyte ds3
the abit AW9D-max (this is my personal favourite)