The iMac "Core i7" 3.5 27-Inch Aluminum (Late 2013) originally was offered as a "configure-to-order" configuration of the iMac "Core i5" 3.4 27-Inch Aluminum (Late 2013), but was sold as a standard configuration, too. Other than processor (and the corresponding level 3 cache), these two models can be identical.
The iMac "Core i7" 3.5 27-Inch Aluminum (Late 2013/Haswell) features a 22 nm "Haswell" Quad Core 3.5 GHz Intel "Core i7" (4771) processor with four independent processor cores on a single chip, an 8 MB shared level 3 cache, 32 GB of 1600 MHz DDR3 SDRAM (PC3-12800) installed in pairs, a a 3 TB "Fusion" Drive , and a NVIDIA GeForce GTX 775M graphics processor with 2 GB of dedicated GDDR5 memory. It also has a built-in "FaceTime HD" webcam and stereo speakers, but lacks an optical drive.
This model has a 27" 2560x1440 LED-backlit 16:9 widescreen IPS display with the "cover glass fully laminated to the LCD and anti-reflective coating." 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 ports, Gigabit Ethernet, 802.11ac Wi-Fi (802.11a/b/g/n compatible), and Bluetooth 4.0.
Apple iMac 27 inch
Keyboard and Mouse not included
Model:MF125LL/A- Late 2013
CPU:3.5GHz Quad Core Intel i7 Processor
RAM:32GB of 1600MHz DDR3 SDRAM
Storage:3TB “Fusion” Hard Drive
Graphics:NVIDIA GeForce GT 755M Graphics
Connectivity: Bluetooth & WiFi
OS: macOS 10.11 or greater