Foo - The Dongle Conundrum

So I have a Radeon HD 6870 with 2 DVI, 1 HDMI and 2 Mini-Display Ports. I wanna connect 3 monitors to it (have currently 2). It is my understanding that I need something called "the dongle". But I don't know if it should be a "passive" dongle or an "active" dongle.

I searched trough my spare parts and found a "Display Port to DVI" Dongle. It has no usb power so I guess it's a "passive" dongle. But the card is *mini*-DisplayPort so it doesn't fit. Should I get a mini-DisplayPort to DisplayPort Dongle and then hook up the DisplayPort-to-DVI Dongle into that? Should one of the dongles be "active"? Does it hurt the card if I make a dongle2dongle connection before reaching the monitor? Kinda like Dongle^2...

I'm very confused.

The less dongles involved, the better.

Each junction in a video cable increases chances for poor display quality, but I am not so sure how that plays out in modern digital times.

I'm surprised the censors will allow you to write "dongle".

I can provide picture of my dongle if necesary.

I can provide picture of my dongle if necesary.

Saw this post in iSpy and was thinking "oh it's one of those threads...".

I know for a fact that Apple makes mDP->DVI adapters. I use a mDP->VGA adapter on my MacBook Pro.

The Apple MDP-DVI adapters only pass digital signals and so are useless if you have an old analog DVI (DVI-A?) monitor. The knock-off ones, on top of being half the price, also pass analog signals. I have a knock-off (Kanex, I think) for my wife's MBP.

Regarding passive vs. active: As I understand it, it depends on the card. If the card has the needed circuitry (the simple existence of the port doesn't tell you anything), you can use a passive adapter, but you'll need an active if it does not. I had to figure this stuff out when an early adopter boss wanted to connect three monitors to his fancy new 12-core computer with a Radeon HD of some numerology a year and a half or two years ago.

I'm not positive, but a native Display Port monitor may make that an irrelevant distinction. I don't think any existed back then.

Hum... I'll look into this. I think there's a non-cheapo version of my monitor model that comes with the native DP (somehow I think spelling out the whole thing "DisplayPort" is better than the abbreviation... specially when referring to the DP Dongles).

Conundrum Update:

Went to the store and found that they no longer carry my monitor (Acer G235H) nor it's fancier version. The tech said the fancier version didn't came with a mini-displayport anyways, just VGA/HDMI/DVI & speakers. The new monitor they carry from Acer is the S321HL which has the exact same dimensions/resolution as my old G235H and comes with DVI & HDMI ports.

I told the tech I wanted to buy 2 monitors *IF* he could test/verify that I could use the 3rd with the HDMI port. He plugged a spare Radeon HD 6870 (my video card) into a test machine, plug the test monitor on a DVI, a new acer on the other DVI and another acer on the HDMI. It worked beautifully, I bought them.

Once at home, installed one monitor on HDMI, tested it, worked great. Installed the other one on DVI and guess what... it worked but the HDMI one went off/disabled. I enabled it and then one of the DVIs went off... what the hell? Did some research and it turns out that only the Sapphire Radeon HD 6870 is able to have 2 DVIs and one HDMI *at the same time*. Mine is a HIS Radeon HD 6870 which doesn't have Sapphire's "FLEX" technology and treats the HDMI port as a DVI, meaning you can use only one DVI when the HDMI is enabled. Oh well...

Then I called customer support for my card and they said it doesn't need to be an active (AKA powered) adapter, a passive one will work just fine. Of course, they indicated it had to be "HIS" brand... found it @ 25 bucks (I expected more) on Amazon and ordered it. According to the tracking page, it's already in Florida and should be here tomorrow.

I can't wait for the adapter to get here. I have a full lineup of first person shooter games already installed, waiting to be played at pure awesomeness x pure awesomeness resolution.

In the mean time, here's a preview of how it's gonna look:

http://i301.photobucket.com/albums/nn53/RubenX_Longwood/Other/101011110957.jpg
(pay no attention to the mess behind the monitors)

That's the G235H in the middle with the two S321HL on the sides. The stands are not the same height so I have to get creative to align them. And there's a slight color temperature difference (expected, calibrable). But it fills the peripheral vision completely.

If the dongle works, I plan to order a 2nd one (still have one mini-displayport available) to install a 4th monitor on top of the center one... a smaller 19 inch widescreen, to use that one as "primary" and keep the windows task bar there. And also to cover some of the mess behind the monitors. :D

PS: Yes, that is a cinder block used as PC stand. Yes the PC is opened for greater ventilation. No is not cocaine on the floor, is boric acid to kill invading roaches.