The Description below is for the dual graphic card variant.
The MacBook Pro “Core i7” 2.8 15-Inch (Dual Graphics/Force Touch – Mid-2015 Retina Display) originally was only available as a “configure-to-order” configuration of the MacBook Pro “Core i7” 2.5 15-Inch (Dual Graphics/Force Touch – Mid-2015 Retina Display), but Apple later added it as a standard option, as well.
The MacBook Pro “Core i7” 2.8 15-Inch (Dual Graphics/Force Touch – Mid-2015 Retina Display) features a 22 nm “Haswell/Crystalwell” 2.8 GHz Intel “Core i7” processor (4980HQ), with fourindependent processor “cores” on a single silicon chip, a 6 MB shared level 3 cache, 16 GB of onboard 1600 MHz DDR3L SDRAM (which cannot be upgraded later), 512 GB or 1 TB of PCIe-based flash storage, and dual graphics processors — an AMD Radeon R9 M370X with 2 GB of dedicated GDDR5 memory and an integrated Intel Iris 5200 Pro graphics processor with 128 MB of “Crystalwell” embedded DRAM (and shared system memory). It also has an integrated 720p FaceTime HD webcam and a high-resolution LED-backlit 15.4″ widescreen 2880×1800 (220 ppi) “Retina” display in a case that weighs just less than 4.5 pounds (2.04 kg). It does not have an internal optical drive.
Connectivity includes 802.11ac Wi-Fi, Bluetooth 4.0, two USB 3.0 ports, two “Thunderbolt 2” ports, an HDMI port, an audio in/out port, and an SDXC card slot.
In addition, this model has a backlit keyboard, a new advanced “Force Touch” trackpad, a “MagSafe 2” power adapter, and an internal, sealed battery that provides an Apple estimated 9 hours of battery life.
Compared to its predecessor, this model is similar, but it has a faster graphics processor, faster flash storage, a higher capacity battery, and a more advanced “Force Touch” trackpad. It has some different identifiers, too.