Seriously, as a result of my wanting to replace my tivo with myth tv (see my other post), i've made the mistake of wanting to plug my fancy PC into my fancy TV and thats where the defecation hit the rotary oscillator.
The first thing to understand is that DVI was meant to be a end-all connector and as such tries to be many things to many people. Every wonder why some cards work with the DVI to VGA adapter and some don't. Well its because not all DVI is created equal.
DVI is actually two standards DVI-A (Analog) and DVI-D (Digital). In the -A standard there are 4 pins that are off to the right with a metal tab between them (ground) which carry the analog signal. The -D uses the pins to the right to carry the signals (see below for more information). The designation of DVI-I is really a DVI-DA or DVI-AD connector. All it means is that the device supports both digital and analog formats.
See the following picture for more information
http://www.lyberty.com/encyc/articles/tech/img/all-DVI-types.jpg
Looking at the Digital connector (or the -I [-AD] version) you see that there is something called Single Link and Dual Link. Dual Link uses more pins than Single Link and basically its a second data bus for the connection (like PCIe 1x vs PCIe 2x)
Dual Link exists so that when there is more data to send to the monitor than one set of wires can handle the data stream can be split increasing the bandwidth. Initially most video card vendors used this as a way to support dual monitors, they would give you a Y cable which was a Dual-Link Male with 2 Single-Link Female's. This limited the combinations of what you could do (only 1 Analog, had to be a specific connector, etc) so they started putting two connectors on the card
But lets explore the limits of Single Link and why you might want Dual Link
DVI signal link supports up to 165MHz of bandwidth (165,000,000/pixels/second) or 3.96 Gbit/s if the reading I've done is correct
1600*1200 at 60 fps = 115Mhz (115,200,000 pixels/second)
1920*1080 at 60 fps = 124.4Mhz (124,416,000 pixels/second)
1920*1200 at 60 fps = 138.2Mhz (138,240,000 pixels/second)
1920*1440 at 60 fps = 165.8Mhz (165,888,000 pixels/second) which is too fast for the single rate, which means that 1920*1200@60fps is the practical limit for SingleLink
DVI dual link supports up to 165MHz of bandwidth (165,000,000/pixels/second) but extends the data range to 7.92 Gbit/s if the reading I've done is correct
As long as the monitor understands that the data is sliced accross two different wires this effectivly increases the bandwidth to 330MHz, but lets call is 2x165MHZ
From Wikipedia:
Example display modes (single link):
HDTV (1920 × 1080) @ 60 Hz with CVT-RB blanking (139 MHz)
UXGA (1600 × 1200) @ 60 Hz with GTF blanking (161 MHz)
WUXGA (1920 × 1200) @ 60 Hz with CVT-RB blanking (154 MHz)
SXGA (1280 × 1024) @ 85 Hz with GTF blanking (159 MHz)
WXGA+ (1440 x 900) @ 60 Hz (107 MHz)
WQUXGA (3840 × 2400) @ 17 Hz (164 MHz)
Example display modes (dual link):
QXGA (2048 × 1536) @ 75 Hz with GTF blanking (2×170 MHz)
HDTV (1920 × 1080) @ 85 Hz with GTF blanking (2×126 MHz)
WQXGA (2560 × 1600) @ 60 Hz with GTF blanking (2x174 MHz) (30" Apple, Dell, Gateway, HP, NEC, Quinux, and Samsung LCDs)
WQXGA (2560 × 1600) @ 60 Hz with CVT-RB blanking (2x135 MHz) (30" Apple, Dell, Gateway, HP, NEC, Quinux, and Samsung LCDs)
WQUXGA (3840 × 2400) @ 33 Hz with GTF blanking (2x159 MHz)
Further Reading on DVI:
http://en.wikipedia.org/wiki/Digital_Visual_Interface
Further Reading on HDMI:
http://www.datapro.net/techinfo/hdmi_info.html
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