Dual 2560x1440 displays

I should point out that I don't intend to game with both, I will switch to single monitor for gaming.

You should be able to. However, I am not up to speed on HDMI specifications so I don't know what resolutions HDMI 1.4 can support.

My primary rig has a Radeon HD 5850 which is connected to 2 monitors using DVI cables. My HTPC has a GeForce 9600GT it is connected to a monitor using one DVI port and to my HDTV using a DVI-to-HDMI adapter.

In general most graphic cards can support two monitors for the past several years; DVI / VGA or DVI / DVI initially. HDMI came into existance more recently so you may have a video card with DVI / DVI / HDMI, DVI / VGA / HDMI, DVI / HDMI or VGA / HDMI.

The video out signal is processed by the RAMDAC and it can only send out 2 video signals. Many video cards have 3 outputs, but that is more for flexiblity and convenience than the actual ability of the video card to output to more than 2 displays.

There are two ways a video card can output to more than 2 monitors:

1. Design the video card with another RAMDAC chip. These video cards are rare, and are somewhat expensive compared to a similar card with only one RAMDAC chip. For example, I believe I remember seeing a Radeon HD 36xx card that could output to 4 monitors, but it cost around $150 more than a typical Radeon HD 36xx card.

2. Get a video card with DisplayPort. DP requires it's own digital signal processor; I think it's called a TMDS module. This is why Radeons with EyeFinity can output to three monitors at the same time.

Nvidia does not have a single card capable of outputting to 3 monitors at the same time. In order to get NVIDIA Surround Vision you must use two GTX 500 cards in SLI to run three monitors at the same time.

Technically speaking, nVidia does have a single card that can output to three monitors at the sametime, the GTX 590. However, the GTX 590 is actually two downclocked GTX 580 GPU chips that are SLI'ed onto a single card.

^^^

Probably more information than you bargained for...

Hi thanks for the response,

Correct me if I'm wrong but I was under the impression the RAMDAC is for analog outputs, not digital. Mostly I'm just wondering if the cards digital management allows for outputting to two 2560x1440 monitors simultaneously, and whether using dual-link DVI is using your 2 outputs or whether it counts as one and the hdmi output is happy to run alongside it. Independently the dual-DVI can run 2560x1440 and hdmi 1.3 (hdmi revision on the monitor) can too. Hdmi revision on the card which is 1.4a is capable of up to 4k x 2k resolution, which is more than enough pixel processing power in theory. (8MP as opposed to the dual monitor setup totaling 7.4MP) So I would assume so. But assumption is not quite enough to purchase this hardware on, and getting such specific information of the interwebs is like trying to get blood out of a stone.

Currently I'm running a single gtx 285 which isn't capable by itself, but which I could use as a second gpu if necessary. However I am trying to keep power consumption down somewhat. Maybe I'll shoot nvidia an email off and see if I get a response.

I miss the days when I thought my 19-inch monitor was a giant, and ran from an 8600gt gpu.

Thanks