some motherboards take quite a bit of time to initialize, so it *could* be normal. Don't know your board though...
What if once you get an image on the screen and then press the reset button? Same story or does it show a picture much quicker?
If it is the same with the reset, I'd tend to say sounds normal to me. If it is showing an image considerably faster, I'd recommend to try another PSU since it could be a defective filter capacitor taking too long to charge up when first powered on.