Sapphire Radeon HD 4890 Video Card - 1024MB DDR5, PCI Express 2.0 x16, CrossFireX Ready, (Dual Link) Dual DVI, HDTV

Monitors come supporting different video connector technologies:  VGA, DVI, DisplayPort, HDMI, or combinations.  Not every monitor supports these, so check the specifications carefully before making your selection.

The Digital Visual Interface (DVI) is the most popular high-quality digital connection for monitors (though HDMI is quickly becoming its equal in popularity).  DVI is a video interface standard designed to maximize the visual quality of digital display devices such as flat panel LCD computer displays and digital projectors. It was developed by an industry consortium, the Digital Display Working Group (DDWG). It is designed for carrying uncompressed digital video data to a compatible monitor or projector, and is partially compatible with the High-Definition Multimedia Interface (HDMI) standard in digital mode (DVI-D).   DVI represents a major improvement in image quality over the older VGA standard. 

The DVI interface uses a digital protocol in which the desired illumination of pixels is transmitted as binary data. When the display is driven at its native resolution, it will read each number and apply that brightness to the appropriate pixel. In this way, each pixel in the output buffer of the source device corresponds directly to one pixel in the display device, whereas with an analog signal the appearance of each pixel may be affected by its adjacent pixels as well as by electrical noise and other forms of analog distortion.

Previous standards such as the analog VGA were designed for CRT-based devices and thus did not use discrete time display addressing. As the analog source transmits each horizontal line of the image, it varies its output voltage to represent the desired brightness. In a CRT device, this is used to vary the intensity of the scanning beam as it moves across the screen.

The two types of DVI interfaces are Single Link and Dual Link. Following are the features and benefits of each:  Single Link - The Single Link interface is limited to a maximum pixel clock of 165 Hz. It uses four (4) twisted pairs of wires (one each of Red, Green, Blue and Clock). Maximum resolution is 1920 x 1200 at 60Hz.  Dual Link - The Dual Link interface is most common for today’s modern LCD monitors. It provides three times as many pixels as the Single Link interface. And its maximum clock may exceed 165 Hz. Dual Link uses six (6) twisted pairs wires with two (2) each for Red, Green, and Blue, as well as a pair for Clock. Dual Link’s maximum resolution is 2560 x 1600 at 60Hz. When you use the Dual Link Interface you can use a longer cable because of its higher bandwidth. Dual Link also provides HDCP support, which is required for Blu-Ray playback.

If your Computer supports DVI ports, but the Monitor does not, then a DVI to VGA adaptor is available at low cost to solve this.  Or inversely, if the Computer output is only VGA, and the Monitor supports DVI, adaptors are available for this as well.  For our selection of Monitor Adaptors click here »

Click Here To Find Video Cards - Look For Dual DVI/Dual Monitor Ready Cards »
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Click Here For Great Deals On A 2nd Monitor »

PCI Express 2.0 - High End Graphics Have Arrived
PCI Express Base 2.0 specification doubles the interconnect bit rate from 2.5 GT/s to 5 GT/s in a seamless and compatible manner. The performance boost to 5 GT/s is by far the most important feature of the PCI Express 2.0 specifications. It effectively increases the aggregate bandwidth of a 16-lane link to approximately 16 GB/s. The higher bandwidth will allow product designers to implement narrower interconnect links to achieve high performance while reducing cost.

A number of optimizations and improvements have been made to the protocol and software layers of the PCI Express architecture in the PCI Express Base 2.0 specification. These include:

• Dynamic link speed management – to control the speed at which the link is operating
• Link bandwidth notification – to notify software (operating system, device drivers, etc) of changes in link speed and width
• Capability structure expansion – to expand the control registers to better manage devices, slots and the interconnect
• Access control services – optional controls to manage peer-peer transactions
• Completion timeout control – to define a required disable mechanism plus related optional enhancements
• Function-level reset – optional mechanism to reset functions within a device
• Power limit redefinition – to redefine slot power limit values to accommodate devices that consume higher power

Will Your Motherboard Support the Video Card You're Purchasing? Here's the Answer...

Before you buy - make sure your motherboard is compatible with this video card. For example, PCI Express video cards won't work with motherboards designed only for AGP or PCI video cards, and vice versa. Please read the specifications carefully or call us for expert advice.

Close-Up: PCI, AGP, and PCI-E (PCI Express)

Check your motherboard and make sure you are purchasing the correct cardbus type.

There are 3 types of cardbus slots currently available: PCI, AGP, and PCI Express (PCIe 2.0 is compatible with PCIe slot)

PCI - The most widely used I/O bus, it provides a shared data path between the CPU and peripheral controllers, such as network, display, SCSI and RAID cards. Though limited in terms of performance, they are considered the best value when you upgrade your video capabilities on a PC. The PCI interface can be found and used in nearly any motherboard.
Click here to view our selection of PCI Cards

AGP - The AGP slot is next in line of higher graphic performance. It was designed especially for the throughput demands of 3-D graphics. It offers up to 8x improvement over a PCI card, is 32 bits wide and runs at 66 MHz. It provides a direct connection between the card and memory, and only one AGP slot is on the motherboard. The motherboard must be equipped with an AGP bus slot for an AGP card to be compatible.(AGP 1x provided a data transfer rate of 264 Mbytes/sec. AGP 2x is 528 Mbytes/sec. AGP 4x is 1 Gbyte/sec. AGP 8x is 2 Gbytes/sec.)
Click here to view our selection of AGP Cards

PCI Express - PCI Express is the newest technology that is superior to both PCI and AGP, in terms of graphic performance. It offers performance as much as 4x faster than the fastest AGP 8X slot. PCI Express connections can support fast data transfer rates, which can be used to connect high-speed devices such as high-end video cards. The slots come in different variations and speeds, such as x1, x4, x8, and x16. Presently, most high-end motherboards meant for design, video production, or gaming come with PCI express slots. To use a PCI Express card, your computer must have at least one available PCI Express slot.
Click here to view our selection of PCI Express Cards