The iMac "Core i7" 4.0 27-Inch Aluminum (Retina 5K, Late 2015/Skylake) technically is a "configure-to-order" configuration of either the iMac "Core i5" 3.2 27-Inch Aluminum (Retina 5K, Late 2015/Skylake) or iMac "Core i5" 3.3 27-Inch Aluminum (Retina 5K, Late 2015/Skylake), but also is documented as a separate model for reader convenience. Other than processor (and the corresponding level 3 cache), this custom model is identical to its stock counterpart.

The iMac "Core i7" 4.0 27-Inch Aluminum (Retina 5K, Late 2015/Skylake) features
a 14-nm "Skylake" Quad Core 4.0 GHz Intel "Core i7" processor (6700K)
with four independent processor "cores" on a single chip,
an 8 MB shared level 3 cache,
32 GB of 1867 MHz LPDDR3 SDRAM (PC3-14900),
a 3 TB "Fusion Drive," and
an AMD Radeon R9 M390 or AMD Radeon R9 M395 graphics processor
with 2 GB of dedicated GDDR5 memory.

It also has a built-in "FaceTime HD" webcam and stereo speakers.

This model has a 27" 5120x2880 LED-backlit 16:9 widescreen IPS DCI-P3 "Retina 5K" display.

The rear of the case is aluminum and is thicker in the middle and tapers to a razor thin 5 mm at the edges.

Connectivity includes
four USB 3.0 ports,
dual Thunderbolt 2 ports,
Gigabit Ethernet,
802.11ac Wi-Fi (802.11a/b/g/n compatible),
and Bluetooth 4.0.

Compared to its predecessor, this model essentially has the same external enclosure, but it has a higher quality DCI-P3 "Retina 5K" display with a wider color gamut as well as a more advanced architecture and graphics architecture.

Please note that stock images are used.