Eyefinity display port - technical necessity or ati being difficult?

D3LTA09

Distinguished
May 19, 2008
163
0
18,690
Sorry if this has already been discussed but could someone just quickly tell me why ATI forces us to use display port to drive one of the 3 monitors used in an eyefinity setup?

I had read somewhere that it was due to the way the outputs were configured on the 5870, in that whilst there is 2 dvi and 1 hdmi the hdmi port is not completely stand alone but is just split from one of the dvi ports so if you wanted to run all three at once it thus wouldnt work - is that even remotely correct? Or is there some other technical reason that requires the use of display port?
Or finally is it just ATI trying to force us to use a format that should have been left to die after hdmi become the common standard?

Also in a cf setup I presume the 3 outputs must all come from one card? ie I have 2 5870s but that doesnt mean I can run 2 dvi on one and an hdmi or dvi on another?

Sorry for the rather noobish questiosn I hadnt really bothered to look into eyefinity seriously as yet because I have yet to find a way to get 3 23" monitors plus my home theatre centre speaker onto a desk without having something hanging from the roof or some such haha.

thanks in advance.
 

hooray4boobies

Distinguished
Mar 6, 2010
111
0
18,710
I'd say they're just trying reach a wider consumer base. To those people with display port capable tv's monitors etc.

Not sure about you, but my two cards came with display port -> hdmi adaptors...so there is no real problem. It could also be the fact it's cheaper to include the dying display port standard with a hdmi adaptor, than paying the rights to include hdmi...who knows?

But wikipedia, as hard to trust as it is, basically states that ATI backed the display port standard before the format war was won. So they had designed the RV870 chip around the display port, and to redesign and remanufacture a different standard wouldn't be in their best interest...plus, display port is capable of hdmi/dvi signals anyway.

As for your your crossfire question, yeah, you can connect up to 6 monitors. across the 2 cards. All 3 ports are seperately driven...that's why they can get 3 seperate resolutions etc.

Hope i didnt miss anything.
 

D3LTA09

Distinguished
May 19, 2008
163
0
18,690
aaah I see, that would make sense. Nah my 5870s didnt come with a dp adapter, must have started including them with the 5900 series.

So in terms of cf if I just wanted a 3 monitor setup I could avoid the display port and use say three dvi ports across the 2 cards? The adapters are rather expensive for just an adapter and Ive heard people having issues with cheap ones so Im trying to find a way around it.
 

hooray4boobies

Distinguished
Mar 6, 2010
111
0
18,710
Hmm...to clarify, as far as i know you can connect 3 seperate monitors to the two seperate cards, but to get the spanned 'eyefinity' mode going...they need to be connected to the one card...i.e. you will need an ACTIVE display port to dvi/hdmi adapter
 

leon2006

Distinguished
Its partly marketing. Thats the recommended next generation video port for computer devices. That is to replace DVI. HDMI require a certain fee to SONY (And its Partners) everytime board vendors put one on the hardware. Display Port is Royalty Free. No money for SONY.

The video vendors are evaluating the market acceptance.


 

plutoporkpie

Honorable
Jun 25, 2012
3
0
10,510


I just posted a lengthy reply to a similar problem a user was having in this other Tom's Hardware thread here.

This is the Active display port to DVi adaptor I currently use to perfectly solve this problem.