Eyefinity 3x1 - Setup & Adapter Questions

[ejohanss69]

Greetings.

I just pounced on the HIS 7870 deal at New Egg for $199 ar. Upgrading from a 5870 that is currently running Eyefinity fairly well 5760x1080.

My Hardware

2 - 23" Samsung LED 1080p monitors with VGA and HDMI connectors
1 - 23" Asus LED 1080p monitor with VGA, DVI, and HDMI connectors

HIS 7870 card with 2 mini displayport, 1 HDMI, and 1 DVI-D outputs

Things I think I know about Eyefinity:

1) 1 monitor can run on the HDMI port. In my case, the second can run off of the mini displayport (converted to DVI or VGA passively). If I want to run a third monitor, it MUST use the mini displayport with an ACTIVE adapter.

2) I own an active displayport to VGA converter. So, I COULD use this for my one "active" DP monitor, and just use passive DP to HDMI for the other two monitors.

2) I am wondering about signal quality, etc. of actively converted to VGA signals. Is there a difference between that and DVI?

3) Would I be better off scrapping the DP to VGA and buying a DP to DVI active adapter, and then running one monitor off of the HDMI, and the other off a mini DP to HDMI passive cable?

More as the thread unfolds...

Thanks in advance.

 

[blastingcap]

I've had both. Use the adapter in a left or right monitor, obviously. Central should be digital.

There is a slight difference and colors will be off, but I would not pay much extra for a DP->DVI adapter if you already have a DP->VGA adapter. Frankly, I would use that third screen for things like youtube videos or less-important stuff anyway. And in games, you are too busy trying to not die, to look over at your left or right screen anyway. It's for peripheral vision, mostly.

 

[ejohanss69]

Furthermore, why can't I find an ACTIVE mini displayport to HDMI cable or converter?

 

[ejohanss69]

OK, so thinking I'll do this:

(left to right)

Samsung (connected via DP active to VGA)
Asus (connected HDMI)
Samsung (connected DVI to passive VGA)

Now, the only issue is that the active DP to VGA I have is full sized DP. Can I convert mini-DP to regular DP, then do the active VGA conversion?

 

[blastingcap]

They make a ton of adapters of all kinds, including miniDP to full-sizeDP and DP->HDMI. Look on amazon or ebay and do a simple search.

 

[ejohanss69]

I can find the DP to HDMI, but I don't think they are active. Haven't been able to find a single one that includes the DAC in the cable.

 

[blastingcap]

I can find the DP to HDMI, but I don't think they are active. Haven't been able to find a single one that includes the DAC in the cable.

All DP->VGA adapters are active. In fact it is impossible to make a passive DP->VGA adapter. So the other two adapters can be passive if you want. For Eyefinity you need at least one active, the other two can be passive. So if you have even ONE active adapter, you are all set.

 

[ejohanss69]

Gotcha...agreed. All DP-->VGA are active. I think this throws some people.

But, I still wonder why I can't find a single ACTIVE miniDP to HDMI cable.