Part 2: AMD's Eyefinity Technology Explained

Features
By William Van Winkle
published

Dangling Issues About Dongles

This first question that might spring to mind as you look over AMD’s dongle chart is why different dongles support different resolutions. According to AMD’s Shane Parfitt, most DACs within passive dongles can only support up to 1920x1200. In looking at VGA monitors, this is fine because most VGA monitors stay at this resolution or lower. True, there are some 2048x1536 CRTs in circulation, and there’s no hard limit on VGA resolution, but there’s no point in designing a dongle product for only a handful of users. People with 30" LCDs capable of 2560x1600 are a lot more likely to use the monitor’s DVI or HDMI port rather than its VGA connection.

If it’s 2560x1600 that you want, then it’s active Dual-Link DVI output you need. Single-Link passive dongles will only get you to 1920x1200. The wiring scheme actually determines a large part of why passive dongles can’t reach the top display resolutions.

Active DisplayPort-to-DVI dongle.

“If you look at the passive dongles,” explains Parfitt, “you’ll notice that we’re using the same output pins as on the DisplayPort connector. Manufacturers actually map that to a TMDS output pin configuration. So right now, TMDS is RGB. That’s four pins, and DisplayPort also has four—the four main links. Yet DisplayPort carries two times the bandwidth of DVI. If you look at the Dual-Link DVI connector, that can support 25x16, but that requires twice as many pins and cables as Single-Link DVI and as DisplayPort.”

AMD splits its dongle validation program into two tiers: Validated and Ready. The company created a kit to send to dongle vendors, enabling them to do much preliminary testing themselves. The kit helps them assess EMI output levels and perform quality signal testing, making sure the dongle correctly passes signals and doesn’t block any data. If the dongle survives the kit’s testing, then the unit is classified as Ready. The vendor can then submit the dongle to AMD, which will then test the device according to Validated criteria. This level is more focused on Eyefinity scenarios and real-world testing. Does it work properly with games? Does it show all expected resolutions? Will it work in three- and six-panel output situations? If so, then it gets the Validated seal of approval.

William Van Winkle
64 Comments Comment from the forums
  • akula2
    I use 3 LCDs with 5770 as well as 5850 cards to run many applications simultaneously. Eyefinity feature offers so much and one could easily avoid buying additional PCs by tapping the features from the processor and the graphics card.
    Reply
  • akula2
    Could someone tell me what happened to the "Print" feature on Tom?
    Reply
  • ckim2116
    It'd be nice if AMD had their own list of Eyefinity supported games. Some of the games on WGF don't work; in fact, the only games that have worked out perfectly for me have been TF2, Batman Arkham Asylum, Torchlight, and L4D2 (all you have to do is select your resolution in the options, in my case 5760x1080). In other games the menu screen just keeps blinking, and attempting to change the resolution just freezes the game.

    Can't wait until all the kinks are worked out!
    Reply
  • cangelini
    akula2Could someone tell me what happened to the "Print" feature on Tom?
    It's right above the comments section, to the right of "Share," amongst a ton of tiny little icons :)
    Reply
  • jsowoc
    I don't see DisplayPort costing that much more. If I look at 22-24" LCDs, the cheapest they come is around $200 for a TN panel or $300 for a PVA monitor, and about $450-500 for an IPS monitor. It's personal preference whether the quality difference is worth the cost.

    If you compare a $200 TN w/out DisplayPort to a $500 IPS w/ DisplayPort, you are comparing apples to oranges. The Amazon price of $220 for a TN w/ DisplayPort is more representative of pricing.
    Reply
  • xrodney
    I am using 30" dell but only way i can use its native resolution is over DVI, on either HDMI or Displayport maximum of 1920x1200 is possible.
    I am not sure if this is limit on DELL only, but as far as I read neither ati 4xxx or 5xxx grapahic card and neither any widely available LCD supports more then that which is quite pitty.
    Even more disapointing is that DHCP working only over single DVI link (1920x1200 max) on DELLs and probably others as well.
    Reply
  • 1898
    Very interesting read, thanks.

    ckim2116
    From the article: http://support.amd.com/us/eyefinity/Pages/eyefinity-software.aspx
    Reply
  • RazberyBandit
    Hmm. Landscape-landscape-landscape seems like it would just be sick for gaming. ASUS monitor bezels are actually angled at the top and bottom. When stacked tightly in such an arrangement, they actually wrap around the viewer nicely. Three 24" 16:9 ratio (1920x1080) monitors stacked sideways yields a HUGE 3:2 ratio (3240x1920 resolution) display. Three 16:10 (1920x1200) monitors end up at 3600x1920. I like this idea better than the far more panoramic view of 5760x1080 or 5760x1200 for most games.

    Alas, I'll be waiting on the next-gen cards and monitors in hopes that prices drop and availability increases. I'd also like to see the proposed standards mentioned within this article actually go into effect, as well as see adoption of display port grow and the technology itself mature.

    Lastly I hope stands adopt a standard that supports landscape-landscape-landscape, portrait-portrait-portrait, and any combination in-between. Having to go out and buy 3 cheap VESA mounts, some metal tubing and round-bar, then get to cutting, bending, and welding my own stand together sounds like a fun project, but I'd rather just buy a mass-produced one.

    Edit: I meant portrait-portrait-portrait...
    Reply
  • gaborbarla
    Bought a 5870 HD the other day.
    Two questions remain for me that I couldnt filter out from these articles by skimming through them:

    1. Why do we need a display port again? I thought the whole point of HDMI was to introduce a digital standard that works with everything TVs Digital signal processors, PCs. Now that most monitors, graphics cards and even some motherboards are starting to support HDMI they come out with a new format... (dot dot dot)

    2. Why does the 5800 series need a display port? why couldn't it have 3 DVI-Ds? So far I haven't even seen a single monitor that has displayport.

    Reply
  • ArgleBargle
    $749 for a dual 5970? I thought a single 5970 cost that much!
    Reply