Never mind. Found this out via Apples own website. Thanks APPLE TECH SUPPORT and STORE STAFF for getting me to buy a useless cable!
Mac Pro Computers (January 2008)
The Mac Pro computers with Quad-Core Intel Xeon 5400 Series microprocessors were introduced in January 2008. The Mac Pros graphics subsystem interfaces to the North Bridge via a 16-lane PCIe 2.0 bus. For information on the PCI Express graphics support and expansion, refer to PCI Developer Note.
The following sections describe the Mac Pros graphics subsystem.
Graphics Cards
Supported graphics cards have dual-link DVI connectors, supporting 30-inch Apple Cinema HD Displays on both ports.
For information on video memory, power, and features refer to Table 1.
All of the supported graphics cards support dual displays in either extended desktop or video mirroring mode; for more detail, see External Display Modes.
Table 1 Supported Graphics Cards
Graphics card
Video SDRAM
Power usage
ATI Radeon HD 2600 XT (standard)
256 MB (GDDR3)
50 W
NVIDIA GeForce 8800GT (configure to order)
512 MB (GDDR3)
110 W
NVIDIA Quadro FX 5600 (configure to order)
1536 MB (GDDR3)
175 W
The GeForce 8800GT graphics card requires that a booster cable be connected from the PCI slot to the auxiliary power connector. The Quadro FX 5600 graphics card requires two booster cables be connected from the PCI slot to the auxiliary power connector. For additional information, refer to the PCI Developer Note.
The Mac Pro supports the 20-inch Apple Cinema Display at a resolution of 1680 x 1050, the 23-inch Apple Cinema HD Display at a resolution of 1920 x 1200, and the 30-inch Apple Cinema HD Display at a resolution of 2560 x 1600. All ports support a maximum resolution of 2048 x 1536 at 32-bit with 85 Hz refresh rate. Multiple PCI Express graphics cards can support three or more displays.
The table below lists the displays supported by port 1 and port 2.
Table 2 Port 1 and Port 2 support
Graphics card
Port 1
Port 2
Radeon HD 2600 XT
20, 23, 30 Apple displays
20, 23, 30 Apple displays, DVI to Video Adapter
GeForce 8800GT
20, 23, 30 Apple displays
20, 23, 30 Apple displays
Quadro FX 5600
20, 23, 30 Apple displays
20, 23, 30 Apple displays
For information on video ports, see Video Monitor Ports. For information on PCI Express expansion slots, refer to PCI Developer Note.
Video Monitor Ports
The Mac Pro has a DVI connector for an external video monitor. For a description of the DVI connector, refer to Figure 4 and Table 30.
The graphics data sent to the digital monitor use transition minimized differential signaling (TMDS). TMDS uses an encoding algorithm to convert bytes of graphics data into characters that are transition-minimized to reduce electromagnetic interference (EMI) with copper cables and DC balanced for transmission over fiber optic cables. The TMDS algorithm also provides robust clock recovery for greater skew tolerance with longer cables or low-cost short cables.
Note: The Mac Pro computer includes a DVI to VGA Adapter.
DVI to Video Adapter
The Radeon HD 2600 XT graphics card supports an optional DVI to S-video/composite adapter that provides S-video and composite output to a PAL or NTSC video monitor or VCR. When a display is connected by way of the video adapter, the computer detects the type of adapter and enables the composite and S-video outputs. The settings for the resolutions and standards (NTSC or PAL) are then selectable in the Display pane in System Preferences.
Note: The DVI to Video Adapter does not come packaged with the Mac Pro computer and must be purchased separately.
The video output connector is a 7-pin S-video connector. Figure 5 shows the arrangement of the pins and Table 31 shows the pin assignments on the composite out and S-video connector.
The Mac Pro computer provides video output at picture sizes and frame rates compatible with the NTSC and PAL standards; the picture sizes are listed in Table 32. Those picture sizes produce under-scanned displays on standard monitors.
