This is just an ad. Compare a $1,700 Mac with an integrated GPU against a $2,400 or $3,500 PC with a discrete GPU on graphics processing tasks. The discrete GPU is gonna win every time.
Honestly, it's not much of an ad, either. The more expensive desktop has less performance per $ than the laptop, and that's before it's running natively!
I guess it boils down to what you need. Sometimes performance per $ matters most and and sometimes you need to hit a minimal performance target for a system to even be worth considering.
