how different is mid-2015 iMac 5k 27" with the late-2015 27" iMac

http://www.apple.com/imac/specs/

Sadly not yet, but you’ll can have an idea comparing here:

iMac (Retina 5K, 27-inch, Mid 2015) - Technical Specifications

https://www.apple.com/imac/specs/

For what I'd saw the base model comes with a AMD Radeon R9 M380 graphics processor with 2GB of GDDR5 memory vs AMD Radeon R9 M290 graphics processor with 2GB of GDDR5 memory.

An all-new sixth-generation Intel Core processor in the 27-inch iMac — at up to 4.0GHz — and 1867MHz memory.

Wider Color Palette. True-to-life color. Alive onscreen: Many of the brilliant, unique colors you see in the real world never make it to your screen. A wider color gamut makes more of these real-life colors available on the Retina display. A striking 25 percent more. So whether it’s a sunset at the beach or your favorite football team’s jerseys, you’ll see them just as you saw them — on a display that’s more vibrant than ever.

And of course for the same price the all-new Apple Magic Keyboard and Apple Magic Mouse 2.

Hope this helps )

I would take it back and order the new one. They have the new processors called skylake from intel. do a search and read up on it.

Hey SlickRick where did you buy the Signal 16GB 1867MHZ DDR3 SO-DIMM PC3-14900 chips from I'm after 2

I have iMac late 2015 27inch 5K Retina 4.0ghz boost to 4.2

Cheers Swiss

I would return and get the new one. When spending this kind of money, go with the most current model.

They are $80 cheaper now. Currently $519. I paid $599 when introduced.

http://eshop.macsales.com/shop/memory/iMac/Retina-5K2015/DDR3L

Absolutely agree 100%

Cool thanks