Why does Eyefinity require an active adapter?

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joe7dust

Limp Gawd
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Jan 25, 2013
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Just curious why you have to buy an ACTIVE (expensive) adapter for setups that don't involve DP monitors. I don't understand why my HD5850 needs an extra 5V just to send that 3rd signal... it already gets a ton of juice from the dual-6-pin power supply connections. Plus that extra 5V is coming from the SAME PC which makes no sense why it couldn't just get the power elsewhere allowing you to buy a $2 passive adapter like DVI-to-VGA.

Disappointed that 2 DVI monitors couldn't be added to my HDMI 42" plasma setup...but I will go ahead and buy this $90 active DP adapter on Amazon because hardware manufacturers are strange and/or greedy! If I'm wrong about that, explain why please. =)

This post has some useful info, but I'd still like to know the exact WHY behind it. I suspect ATI could flash the FW/BioS to make the 5000/6000 series cards support 3 displays natively, but they are really bad in the support area for things like that. They usually just want you to buy the newer cards, download the ever-bloating CCC software and shut up. I actually was banned from the ATI forums for complaining about their bad drivers on the HD5850.
 
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What exactly are you hooking up? Most people get by fine with $20 DP to DVI adapters (which are active).

Update: using the Sapphire adapter with 6850 and 7850 cards.
 
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Good luck is all I can say. I have had Eyefinity and I went through 7 adapters before I got 2 that worked. By the time I had the setup working I could have almost bought a 3rd video card on the Nvidia side. I can't really understand the need for the active DP adapter either, AMD insists that DP is the future but years later there are still not really any monitors using them.
 
joe7dust said:
This post has some useful info, but I'd still like to know the exact WHY behind it.
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It explains exactly why:
DVI/HDMI requires a special clock, which the card is only able to provide two of. Displayport does not use this clock
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Active adapters are not really adapters. They are converters. The video card outputs a DisplayPort signal, and the active adapter converts the signal to DVI/HDMI to send to the monitor. The USB plug is to power the converter, not the video card. You don't need a $90 active converter unless you need dual-link DVI. There are $30 active converters for single-link DVI, and those don't need USB power.

Passive adapters don't do any conversion. They simply change the shape of the port and reroute the pins. The video card will then output a DVI/HDMI signal through the adapter. Using a passive adapter is no different from using a DVI/HDMI port, so it will use up one of the two clocks. DisplayPort does not have enough pins to adapt into a dual-link DVI port, which is why a $90 active converter is required for dual-link DVI.
 
It sounds like a bit of a hardware design flaw to me. Why make a card with 2 dvi and a hdmi that can't all be used under normal conditions? I'm probably going to get a $20 one that uses the DP's 3.3v line to power the conversion.
 
They have all those port for connectivity options, not everyone has the same display devices.
 
Yea but the card is marketted as supporting eyefinity which requires 3 simultaneous connections. No where on the box does it say hey btw youre going to need an overpriced converter to actually make our marketing claims come true.
 
Eyefinity doesn't require 3 simultaneous connections, only 2. It can support up to 6 connections for crazy people <raises hand>. Given that most new monitors have native Displayport connectors and the adapter is not a major cost issue if you require single-link resolutions (1080p) I personally don't see the problem. If you are hooking up multiple 30" monitors that don't have Displayport *THEN* it hurts as you need the $100+ dual-link adapters. I know, I have 3 30" monitors in Eyefinity and I needed to get 2 of those adapters, though I got lucky on a used one for $20.
 
So this active display port converter is so complex that they couldn't include it on the graphics board, not even as a daughter card of some sort? Not like anyone would expect such a thing on a $400+ graphics card or anything.
 
rtangwai said:
Eyefinity doesn't require 3 simultaneous connections, only 2. It can support up to 6 connections for crazy people <raises hand>. Given that most new monitors have native Displayport connectors and the adapter is not a major cost issue if you require single-link resolutions (1080p) I personally don't see the problem. If you are hooking up multiple 30" monitors that don't have Displayport *THEN* it hurts as you need the $100+ dual-link adapters. I know, I have 3 30" monitors in Eyefinity and I needed to get 2 of those adapters, though I got lucky on a used one for $20.
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I thought the defnition of Eyefinity was 3 monitor or more... what good is 2 monitor Eyefinity exactly?
 
joe7dust said:
Yea but the card is marketted as supporting eyefinity which requires 3 simultaneous connections. No where on the box does it say hey btw youre going to need an overpriced converter to actually make our marketing claims come true.
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Technically if you had a DP monitor, you wouldn't need an adapter, but I understand your point.
 
joe7dust said:
I thought the defnition of Eyefinity was 3 monitor or more... what good is 2 monitor Eyefinity exactly?
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Eyefinity specifically means using two or more monitors as one giant screen. That's all it means, it has absolutely nothing to do with the number of monitors.

The scenario you're describing is extended display mode, where each monitor is independent of each other. True, it is easy to get the two mixed up for 3 or more monitor displays, due to the fact that eyefinity and mainstream cards that can support 3 or more monitors at the same time appeared at the same time, but they're two completely different things.

As for needing to place an adapter on each card... imagine needing to put a $90 DP to dual-link DVI adapter on each card. That would drive costs through the roof, and take up significant board space as well as output on the back panel. mDP connections are tiny, while dual-link DVI are huge. You can only fit two dual-link DVI connections in the space of 6 mDP connections, and only two dual-link DVI per row. If you had both rows occupied by dual-link DVI connections, where would the card exhaust to?
 
Oh I get it.. it is just so games can fullscreen spread across both. I'm surprised noone has come up with a driver-hack or firmware that allows merging 2 monitors into one like this instead of extended desktop.
 
joe7dust said:
Oh I get it.. it is just so games can fullscreen spread across both. I'm surprised noone has come up with a driver-hack or firmware that allows merging 2 monitors into one like this instead of extended desktop.
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They have, it's called SoftTH but it certainly has it's limitations.
 
Would it be possible to use 2 of my monitors as a fused display with this on 2 dvi ports and still get hdmi to my main display? Not trying to be a cheapass but im not actually planning to use eyefinity for gaming rather 2 satelite displays to augment 1 gaming display
 
It's called "compatible hardware". The sapphire "Flex" cards can do 3 screen Eyefinity without using displayport (2xSL DVI + HDMI). Other than that at least one of your monitors needs to have displayport. Or, you need to use an active adapter. As has been noted, you don't need a DL DVI adapter (the ~$100 ones) unless you are running 2560*1440-1600, you can use the cheaper SL DVI (~$30).

Most better monitors have displayport inputs. Worse case are the cheap Korean 27" monitors people are buying that only have DL DVI inputs. With those you'll need 2x DP to DL DVI adapters (The $100 ones).

Just be sure your hardware is compatible or buy the needed adapters. It's been like this for years with Eyefinity. It's not like it's an unknown requirement.



This is noted on manufacturers websites with the Eyefinity feature.
*To support 3 displays, one of the monitors has to support DisplayPort
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joe7dust said:
Could i hook up 4 displays?
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If you want Eyefinity you need to use a 6xxx or 7xxx with 2 or more DisplayPort outputs (unless you get a Sapphire FLEX as noted above). If you just want multiple monitors you can add a second video card, doesn't matter which one if you are using Windows 7 (it *DOES* matter in Vista due to driver limitations).

The reason for Eyefinity limitation is that Eyefinity will span only across monitors hooked to the *SAME* card. That restriction becomes doubly so if you also do Crossfire as only one card's outputs are active in Crossfire.
 
It's the exact reason why I swapped over to nVidia. They can power 4 screens with 1 card no special adapters needed.

However, depending on what your situation is, if you are trying to power a 3rd screen that is running @ 1080p resolution, you don't need any real expensive ACTIVE adapter. The one I use to have costs like ~$15. The ~$100 ACTIVE adapters are for the 2560x1440~1600 resolution.
 
JL6speed said:
It's the exact reason why I swapped over to nVidia. They can power 4 screens with 1 card no special adapters needed.
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Can't power 4x 2560 x 1440 or 4x 1920 x 1080 120Hz, can they?
Actually, what nV card has 4x DVI/HDMI? Most have just 2x DVI + 1x HDMI. How would you power the 4th non-DP screen?
 
JL6speed said:
It's the exact reason why I swapped over to nVidia. They can power 4 screens with 1 card no special adapters needed.

However, depending on what your situation is, if you are trying to power a 3rd screen that is running @ 1080p resolution, you don't need any real expensive ACTIVE adapter. The one I use to have costs like ~$15. The ~$100 ACTIVE adapters are for the 2560x1440~1600 resolution.
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+1. When I run eyefinity I use the 2 dvi's and the DP port with the really cheap adapter, and it works great, but its only 1080 like you said.
 
XTF said:
Can't power 4x 2560 x 1440 or 4x 1920 x 1080 120Hz, can they?
Actually, what nV card has 4x DVI/HDMI? Most have just 2x DVI + 1x HDMI. How would you power the 4th non-DP screen?
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Imo, if you are powering 4x 2560x1400, you'd probably want to SLI anyways. However, the card does have 2 DL-DVI, so technically it can power that high of resolution. I'm not personally familiar with what HDMI/DP can max at, but I assume it can handle it as well.

Also if you run a lot of monitors @ 1440-1600p resolution, you will hit a wall with the 2GB ram. Something to take in account. So if you are running 3+ 1440-1600p for surround gaming, you'd probably want to look into AMD too as multi gpu setups would be needed and AMD does have more video ram.
 
rtangwai said:
If you want Eyefinity you need to use a 6xxx or 7xxx with 2 or more DisplayPort outputs (unless you get a Sapphire FLEX as noted above). If you just want multiple monitors you can add a second video card, doesn't matter which one if you are using Windows 7 (it *DOES* matter in Vista due to driver limitations).

The reason for Eyefinity limitation is that Eyefinity will span only across monitors hooked to the *SAME* card. That restriction becomes doubly so if you also do Crossfire as only one card's outputs are active in Crossfire.
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Thsts misinformation. Ive read of several 58xx and 57xx cards running 3. Im going to do it with a 5850

CrazyRob said:
They have, it's called SoftTH but it certainly has it's limitations.
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joe7dust said:
Would it be possible to use 2 of my monitors as a fused display with this on 2 dvi ports and still get hdmi to my main display? Not trying to be a cheapass but im not actually planning to use eyefinity for gaming rather 2 satelite displays to augment 1 gaming display
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If someone could please answer this by Monday it will save me 20&#8211;30$
 
joe7dust said:
Thsts misinformation. Ive read of several 58xx and 57xx cards running 3. Im going to do it with a 5850





If someone could please answer this by Monday it will save me 20–30$
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I will second the 58xx cards running 3 lcd's in eyefinity, unless I was dreaming!(or crazy) :p
 
joe7dust said:
Thsts misinformation. Ive read of several 58xx and 57xx cards running 3. Im going to do it with a 5850





If someone could please answer this by Monday it will save me 20–30$
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You're absolutely right, they can run 3 - but I was answering the question "Can you run 4 displays?"
 
Also, SoftTH does not get around the need of an active display port adapter for the third screen. It's just a software solution for merging multiple displays into one virtual display without the use of eyefinity or surroundview.
 
CrazyRob said:
Also, SoftTH does not get around the need of an active display port adapter for the third screen. It's just a software solution for merging multiple displays into one virtual display without the use of eyefinity or surroundview.
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Ok thanks Ill go ajead and get the adapter. I thought mabye since im not going to eyefinity I could use that to get around it.
 
who doesn't have display port monitors at this late date?
 
jojo69 said:
who doesn't have display port monitors at this late date?
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Anybody who wants cheap 27" or 30" (Korean, used XHD3000/305T, etc.). I have 7 monitors attached to my computer and not one of them has DisplayPort, I use 4 adapters (two dual-link, two single-link) to make it all work.
 
jojo69 said:
who doesn't have display port monitors at this late date?
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How's the weather up there on that high horse? My 3 year old 42" plasma still looks delicious for gaming. Might replace it with a 60+ someday and that wont have DP either most likely.
 
rtangwai said:
Anybody who wants cheap 27" or 30" (Korean, used XHD3000/305T, etc.). I have 7 monitors attached to my computer and not one of them has DisplayPort, I use 4 adapters (two dual-link, two single-link) to make it all work.
Click to expand...

Now that's some productivity lol
 
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