i would guess so but i would think that they are other factors involved. for e.g. a pc program might require a 900mhz cpu for it to run properly but a the same program on a mac might only require a 600mhz and visa versa (btw that was just a guess it may or may not be true)
Yes they are relatively close. Macs also tend to have an advantage in the graphics area as well. My friend is a graphics designer and does a great deal of work with Adobe products at home and he has an old 400mhz Mac. It does the job just fine. I wouldn't dream of doing Adobe Photoshop, illustrator, etc on anything near a 400mhz on the PC platform.
Mac has a difrence a 900 mhz mac is more powerfull then a 900 mhz Pc Intel Amd cpu .... it's just a litlle bit difrent ....
im using a 2ghz pc. I want to buy an imac to turn it into an arcade machine, just not sure if its going to be powerfull enough. =)