I had the chance to edit our iPad Air 2 review on this machine, using the new iMac and Adobe Premiere. It’s fast: there was zero lag or delay in playing back 1080p footage on a timeline, even with a moderate number of real-time color effects in play. Scrubbing through a timeline is extremely responsive, probably thanks to our review unit’s 1TB solid-state drive. I was particularly impressed with Premiere’s ability to immediately begin reverse playback on the timeline, something which other Macs in our office, including the Retina MacBook Pro, seem to struggle with. It’s quite nice to work with HD video with this monitor

http://www.theverge.com/2014/10/27/7068363/apple-imac-with-retina-5k-display-review

I also saw controversial reports, one mentioned it as 30Hz and others (without any measurements and actual proving) as 60Hz.

@ADCfilms October 21

"Vitaliy, would you or anyone else knowledgable here consider this iMac (judging by the spec), paired with Thunderbolt drives, a reasonable editing solution to work with a 4k raw BMPC workflow?"

Well it depends.

The crippled laptop GPU isn't exactly what you want for 4k RAW. When you deal with Resolve, you need an external i/o box for color grading, since the Mac is still limited to 8bit, and the viewer window isn't colormanaged anyway.

If you only edit @1/4 resolution, it would probably be okay, but for the money you could build a nice PC with way more umph.

Apple is updating the 27-inch iMac today with better specs and a better display. To start, Apple is making every model of the 27-inch iMac ship with a 5K display, which means you can now get that higher resolution for $1,799, rather than the previous starting price of $1,999. That 5K display is also getting a lot nicer, with Apple saying that it can display up to 25 percent more colors

http://www.theverge.com/2015/10/13/9512503/apple-imac-update-27-inch-5k-price-release-date-specs

2019 ones