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Ati 7850 Three monitors on DVI-I + HDMI + DP(active to dvi-d) ?

Last response: in Graphics & Displays
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February 25, 2013 11:35:53 AM

Hello,

i have Sapphire 7850 2GB that has DVI-I, DVI-D, HDMI and DISPLAYPORT output.

Iam currently running the two displays on it:
DVI-I output -----> DVI-I to VGA adapter ------> VGA Display (It only has vga input)
DVI-D output ---------------------------------> DVI-D Display (it also has hdmi input and it works if i connect it like that instead of the dvi)

Now i want a third display which will be either Dvi-D input only, or both Dvi-D and Hdmi. It wont have displayport.

I want to run a three monitor setup just for extended desktop space, not Eyefinity. I read sapphire forum post about multimonitor setup (http://www.sapphireforum.com/showthread.php?28155-EWP-G...) and learned that i can only use two ports out of the DVI-I, DVI-D and HDMI combination and then the Displayport needs to be used for the third display for this to work. (With a display that either has direct Displayport input or else using an active DP->DVI-D adapter).

But their post keeps talking about DVI-D connection in all of the examples and theres no mention about the DVI-I port being an option too. So this leaves me wondering if it will work without having to replace the vga display as well.

This is my idea when i get third monitor and active adapter:
DVI-I output -------------> dvi-i to vga adapter ----------> vga monitor (this is what i worry about, using Dvi-i port and not Dvi-D as they show in the post)
HDMI output ---------------------------------------------> hdmi monitor (it has dvi-d as well)
Displayport output -----> DP to DVI-D active adapter -----> Dvi-d monitor (this will be the third new one, probably will have hdmi input too)


Thanks in advance for any kind of help!
February 25, 2013 11:45:04 AM

correction:
displayport to vga adapter to vga monitor (both analog)
dvi-i/d to dvi monitor
dvi-i/d to dvi monitor
*or hdmi to hdmi monitor (if speakers on monitor)
February 25, 2013 11:49:40 AM

one monitor will need to be on dp, i would get one of these approved dongles. they say they are for eyefinity, but i got one of the cheap ones and I had problems with it droping the connection. http://support.amd.com/us/eyefinity/Pages/eyefinity-don...
having one of the signals converted to vga will bring down the quality of the dp monitor, so you should think about upgrading in the future if it bothers you.

possible setups
1 dvi 1hdmi 1 dp (you cannot use the dvi + hdmi on the same row)
2 x dvi 1 dp
1
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February 25, 2013 12:13:01 PM

Thanks for swift reply guys,

- So by the "row" i guess you mean the lower row of connectors on gpu where DP, HDMI and DVI-I are in one row. I need to use one vga monitor but i dont think i can get an active DP->vga adapter here, so that means i need to use the DVI-I for it and thats in the hdmi row, so that disallows the use of hdmi which is no problem.
- Then i use the "upper row" solo DVI-D for dvi monitor
- and then i get active DP->dvi-d adapter for third monitor (will this do? "sapphire dp to dvi single-link" but description says for hd5xxx and hd 6xxxx http://www.dvhardware.net/news/2010/sapphire_displayport_to_dvi.jpg) Im not sure if i can get any other within my country easily.

So that way it is like:
(upper row solo) DVI-D ----------------------> dvi display
(lower hdmi row) DVI-I ----> dvi-i to vga ----> vga monitor
Displayport ---------> active DP to DVI ------> dvi monitor

Should i get dual-link cables too or is that not a problem? I wont need resolution above 1920x1200 in the future tho.
February 25, 2013 12:17:45 PM

you don't need an active adapter or converter, it's much cheaper and better to get an adapter to use your vga monitor with your displayport and use your dvi connections with dvi monitors
February 25, 2013 12:41:36 PM

Hmmm ok, well i have trouble finding a cheap dp->vga adapter here, they are in the same range of the active dp->dvi ones eventho they dont seem to be active and i will have to order from abroad unless i give the sapphire dp->dvi one a succesful try first. Other than that there is loads of miniDP->vga ones tho, but this card has the standard DP.

Anyways thanks alot for the input, it definitely cleared alot of things up and i will see how it goes. I actually have another vga display here, i might try using that as the third one first if i manage to get the DP-vga adapter, i didnt know that DP could be converted to vga and work in three screen setup.
February 25, 2013 1:13:13 PM

Thanks for links. I can get a dp->dvi-i here, if i further put dvi-i -> vga adapter on that, that should work the same way, right? i never knew displayport had analog signal in it so unless the pins on the dp-dvi-i adapter are just fake holes, it should work
February 25, 2013 1:51:27 PM

I don't think it will work as well, but it won't hurt to try. good luck
February 26, 2013 12:13:27 PM

Ok so i tried this DP->DVI-I adapter ( http://www.alfacomp.cz/ezbozi/2/30521/64982as.jpg )
There was no mention about it being active tho, it just has a led indicator. Cost bit more than the one suggested at amazon.

So i tried:
DP->DVI-i adapter ---> dvi-i -> vga adapter --------> vga monitor

- no signal, even when solo connected like this

DP->DVI-i adapter -----------------> dvi monitor
- worked fine solo

Then i tried three displays with that:
DP->DVI-i adapter -----------------> dvi monitor
(upper)Dvi-d ------------------------> dvi monitor
(lower)Dvi-i ----------> dvi -> vga adapter ------> vga monitor

- then only the ones connected to direct dvi ports worked and the third one in the DP behaved the same like when i try connect three without using DP, meaning it wont let me extend desktop there but i can duplicate signal of one of the dvis to there.

That makes me think i really need a proper active adapter for the DP and these simple dp->vga / dvi adapters wont do the job.

I wonder how this behaves on nvidia cards (gtx660 specifically, anyone has experience with that? do they need active adapters for 3+ monitors?)
February 26, 2013 2:59:59 PM

was the dvi adapter active (converter)? the dp to dvi should be passive, just translating dp to dvi-a analog signal, and the dvi to vga should also be passive, changing only pin location.
March 2, 2013 12:33:31 PM

Yes the dp->dvi-i adapter and then the dvi-i->vga on top of it were both passive and it didnt work, i could only duplicate to that display but not extend.

So then i bought active DP->DVI one (http://3dvision-blog.com/wp-content/uploads/2011/03/sap...) which made it work with dvi monitor but to my surprise it was actually DVI-I port going off the adapter so i couldnt resist trying to put the passive dvi-i->vga adapter on it and connect vga monitor but that produced no signal again.

so the working setup is indeed:
1dvii (dvi to vga --> vga monitor)
1dvid (dvi monitor)
1dp (active dp->dvi --> dvi monitor)

(so i guess 7850 with this port setup can run 3 screens max, it would have to have two miniDP ports for four separate screens)

So i guess its simpler solution to just update vga displays for dvi ones rather than trying to fight it with adapters on top of adapters, especially if active dp-> vga ones arent locally available to buy and test. So i get rid of the vga displays and will only use dvi/hdmi to avoid problems in future. Iam very likely gonna try playing around with the ati flex cards in the future too, which can aparently output to 5 monitors separately even without active adapters on the DPs.

Anyways thanks for the help here guys
!