What are the default graphics cards provided with the Gray Cylinder Mac Pro? What graphics card options are available? How do you upgrade the graphics card(s)? Do these models use standard PC graphics cards?

The standard Cylinder Mac Pro models both have dual graphics cards.

Specifically, the entry-level Mac Pro "Quad Core" 3.7 has dual AMD FirePro D300 graphics processors with 2 GB of GDDR5 memory each and the higher-end standard Mac Pro "Six Core" 3.5 has dual AMD FirePro D500 graphics processors with 3 GB of GDDR5 memory each.

Photo Credit: Apple, Inc. (Cylinder Mac Pro - Back, Left; Graphics Cards Visible, Right)

Standard & Custom Configured Graphics Cards

In addition to the standard dual AMD FirePro D300 and D500 graphics cards, Apple offers dual AMD FirePro D700 graphics cards each with 6 GB of GDDR5 memory as a US$1000 upgrade for the entry-level Mac Pro "Quad Core" 3.7 and a US$600 upgrade for the Mac Pro "Six Core" 3.5.

The technical differences between these three graphics cards include the following:

AMD FirePro	GDDR5 Memory	Stream Processors	Memory Bus	Memory Bandwidth	Teraflops Performance
D300	2 GB	1280	256-Bit	160 GB/s	2.0 Teraflops
D500	3 GB	1526	384-Bit	240 GB/s	2.2 Teraflops
D700	6 GB	2048	384-Bit	264 GB/s	3.5 Teraflops

For those interested in how these graphics cards compare to AMD's offerings for PCs, the always detailed AnandTech did some digging and reported that the "D300 is Pitcairn based, the D500 appears to use a Tahiti LE with a wider 384-bit memory bus, while the D700 is a full blown Tahiti XT."

Preliminary Upgrade Information

Officially, only the memory and SSD storage in the Cylinder Mac Pro are designed to be upgraded by end-users. Apple does not state whether or not the graphics processors can be upgraded.

However, as first confirmed in a teardown by site sponsor Other World Computing, both graphics cards are removable.

Photo Credit: Other World Computing (Cylinder Mac Pro Graphics Card Removed)

These graphics cards are custom designed for the Cylinder Mac Pro, and although they use a PCI 3.0 x16 interface, the Cylinder Mac Pro is not compatible with any standard Mac or Windows compatible PCIe video card. Both the physical dimensions of the card and the connector are specific to the Cylinder Mac Pro.

Unlike earlier Mac Pro models that have industry-standard PCIe slots and support a fairly wide variety of video cards as a result, the Cylinder Mac Pro models would require third-parties to create video cards specifically for the Cylinder Mac Pro.

Third-parties very well may create custom video card upgrades, but as the Mac Pro typically does not sell in high volumes, it may be difficult for companies to justify the unique development time and cost. Given lower volume, it also likely will mean that any graphics cards released will be considerably more expensive than standard PCIe video cards.

Ultimately, even though it is technically possible, only time will tell if third-parties release graphics cards for the Cylinder Mac Pro.

What is the maximum resolution supported by the default configuration of the Gray Cylinder Mac Pro? How many displays can it support with the default graphics card?

Regardless of the graphics cards installed in the Gray Cylinder Mac Pro -- the dual AMD FirePro D300 or D500 graphics processors that are provided by default or the dual FirePro D700 graphics processors that are available as a custom upgrade -- the maximum supported resolutions and number of displays are the same.

Originally, Apple specified that each Cylinder Mac Pro supported as many as three 4K displays (3840x2160) -- two using Thunderbolt 2 ports and one using the HDMI port -- or as many as six 2560x1600 displays using all six Thunderbolt 2 ports.

However, on June 16, 2015, without updating the graphics cards themselves, Apple quietly increased the official support to as many as three 5K displays (5120x2880) -- two using Thunderbolt 2 ports and one using the HDMI port. The support for as many as six 2560x1600 displays using all six Thunderbolt 2 ports remained unchanged.