its all about program support, if you have a Vista you are fine (everyone supports it) if you have a MAC you need to find special programs , if you have a linux you can use both but not 100% everything (like Microsoft based flash games or Itunes)

Use sims 3 to judge

Macs tend to be much slower for the price. The Macbook Air, for example is incredibly slow for the price.

short answer it's no.

the thing is microsoft vista/7 is slow.
get rid of it and you get less 15s seconds boots in ubuntu.

and less than 10s its promised for 9.10

your pointing out an incredibly specialized computer that puts portability, style, battery ahead of  speed. why not compare an 8 core mac pro to a similar computer. 

Okay then, how much does this 8 core Mac cost?

i believe the base is 3,300. for 2 quadcore xenon 2.26   6 gb ddr3 1066mhz.    

Well at turning on.

It takes like 10s to unhibernate a PC with Vista. I don't see how even if its faster it would really matter to anyone.

Too many variables and it doesn't take the user itself into account as well.

No way to really tell.