Apple revealed the features of their new 27-inch Retina iMac with 5K display during a live broadcast online.

The screen has 14.7 million pixels. To put that into perspective, Apple's Jeff Boudier compared it to the HD TVs that many people watch at home. He said the Retina Mac has seven times more pixels than an HD TV.

"It is stunning," he said at the Apple event while presenting the Retina iMac.

It stands out from the regular 27-inch Mac because of these extra pixels and it has a stronger Intel Core processor. 

Apple also invented their own timing controller (TCON) to control the pixels in the Retina iMac at a faster speed than any other existing TCON.

"The new 27-inch iMac is by far the best iMac we ever built," Apple says in a video at the event.

Boudier says that the Retina iMac is especially impressive because it "took a lot of invention" and it's only 5 millimeters thick.

The 27-inch Retina iMac 5K costs $2,499.