It's a reasonable question. My answer is: Thunderbolt.
The only Apple display that can simulate pixel-for-pixel an iPad Retina display is the (discontinued) 30", and only in landscape orientation. The only way to test a Retina Mac app today (short of buying a new Macbook Pro) is to view it double-size.
I know bigger-than-15" Retina displays would be super-expensive today, but I assume the eventual Retina external displays will be (like the current 27" display) Thunderbolt-only, and that Thunderbolt requires CPU/chipset support (right?), which makes it sound to me as though no current Mac Pro will ever show (correctly-sized) Retina content.
That's not a dealbreaker for me today, but Mac Pro buyers tend to buy them to last for several years. Nobody really wants to pay more for a new expandable machine that only supports an end-of-life expansion port. A Thunderbolt Mac Pro would at least stand a good chance of being Retina-upgradeable (with a new graphics card).
The only Apple display that can simulate pixel-for-pixel an iPad Retina display is the (discontinued) 30", and only in landscape orientation. The only way to test a Retina Mac app today (short of buying a new Macbook Pro) is to view it double-size.
I know bigger-than-15" Retina displays would be super-expensive today, but I assume the eventual Retina external displays will be (like the current 27" display) Thunderbolt-only, and that Thunderbolt requires CPU/chipset support (right?), which makes it sound to me as though no current Mac Pro will ever show (correctly-sized) Retina content.
That's not a dealbreaker for me today, but Mac Pro buyers tend to buy them to last for several years. Nobody really wants to pay more for a new expandable machine that only supports an end-of-life expansion port. A Thunderbolt Mac Pro would at least stand a good chance of being Retina-upgradeable (with a new graphics card).