6 replies to this topic

[PWNZOR]

So I was looking at graphics cards recently for a possible upgrade based on some online deals.
I mean, my current card isn't bad in the least, but an upgrade might be worth doing so if the deal is good enough.

I have a Zotac GeForce GT 440 currently, which has a single DVI port on it. Looking at some of the GTX models, like the 650, have double DVI ports.
I assumed that having another DVI port would allow for an extended desktop or support for dual DVI port monitors (the ones that require two DVI plugs because their dimensions are ridiculous, like 2300+ wide). However, my dad was telling me that a single DVI port has support for extended desktop by itself with a y-cable, even with a 1920 x 1080 monitor for each desktop.

But if this is so, then does that mean these GTX cards can support 4 extended desktop monitors at 1920 x 1080 off a single card? That seems a little overkill to me, which is what I am wondering. Each DVI port on the card can support two extended 1920 x 1080 monitors at full resolution?

If I am to upgrade to extended desktop, I won't be getting 4 total monitors: only 2, which means I don't need a dual DVI card with this information. That saves money, but I want to be sure.

Thanks,
PWNZOR

[TheDoctor]

I have one DVI monitor and one VGA monitor. Don't buy a card based on what monitor configuration you're going to use, unless you have something like 8 monitors which is ridiculous. Most if not all of the 600 series have two DVI, one HDMI and one DisplayPort. If you need a more powerful GPU, buy it for that. I would suggest a 660 TI.

[JrMasterModelBuilder]

I was under the impression a Y splitter just split the same single screen onto both screens and doesn't give you an extended desktop. Based on the maximum DVI output I found on Wikipedia, I really doubt it could manage 2 screens at that reslution, at least not at 60 Hz.

The DVI specification mandates a maximum pixel clock frequency of 165 MHz when running in single-link mode. With a single DVI link, the highest supported standard resolution is 2.75 megapixels (including blanking interval) at 60 Hz refresh. For practical purposes, this allows a maximum screen resolution at 60 Hz of 1,915 × 1,436 pixels (standard 4:3 ratio), 1,854 × 1,483 pixels (5:4 ratio), or 2,098 × 1,311 (widescreen 16:10 ratio).

[Phoenyx]

I was under the impression a Y splitter just split the same single screen onto both screens and doesn't give you an extended desktop. Based on the maximum DVI output I found on Wikipedia, I really doubt it could manage 2 screens at that reslution, at least not at 60 Hz.

It works if you use a DVI to 2xVGA splitter, but not a straight Y-splitter.

[PWNZOR]

Okay, thanks guys.

What about the cards that are dual-link DVI? Do they support extended desktop on each port or do they only use the second port for the huge wide monitors?

[TheDoctor]

Okay, thanks guys.

What about the cards that are dual-link DVI? Do they support extended desktop on each port or do they only use the second port for the huge wide monitors?

Stop thinking about dual-link DVI. You don't need it. The only reason you would need it is if you were getting an old card, which you aren't, or if you have a stupidly huge monitor, which you don't have. Dual link DVI is for increasing video bandwidth. That's it.

Spoiler

Example display modes (single link):
- HDTV (1,920 × 1,080) @ 60 Hz with CVT-RB blanking (139 MHz)
- UXGA (1,600 × 1,200) @ 60 Hz with GTF blanking (161 MHz)
- WUXGA (1,920 × 1,200) @ 60 Hz with CVT-RB blanking (154 MHz)
- SXGA (1,280 × 1,024) @ 85 Hz with GTF blanking (159 MHz)
- WXGA+ (1440 × 900) @ 60 Hz (107 MHz)
- WQUXGA (3,840 × 2,400) @ 17 Hz (164 MHz)

Example display modes (dual link):
- QXGA (2,048 × 1,536) @ 75 Hz with GTF blanking (2 × 170 MHz)
- HDTV (1,920 × 1,080) @ 85 Hz with GTF blanking (2 × 126 MHz)
- WUXGA (1,920 × 1,200) @ 120 Hz with CVT-RB blanking (2 x 154 MHz)
- WQXGA (2,560 × 1,600) @ 60 Hz with GTF blanking (2 × 174 MHz) (30-inch or 762-millimetre Apple, Dell, Gateway, HP, NEC, Quinux, and Samsung LCDs)
- WQXGA (2,560 × 1,600) @ 60 Hz with CVT-RB blanking (2 × 135 MHz) (30-inch or 762-millimetre Apple, Dell, Gateway, HP, NEC, Quinux, and Samsung LCDs)
- WQXGA (2,560 × 1,600) @ 60 Hz with CVT-RB blanking (269 MHz) (This is for high end monitors when operating at greater than 24 bits per pixel.)
- WQUXGA (3,840 × 2,400) @ 33 Hz with GTF blanking (2 × 159 MHz)

[PWNZOR]

Alright, okay. One DVI port per separate monitor, dual-link or not.
Dual-link DVI can be used to split into two VGA, or for a 'stupidly large monitor' as you call it, but that's it.