Why did they not share the HDMI port with the DP

bowenac · Post by **bowenac** » 01 Dec 2009, 01:08

First hello to all first post.

Ok I have 3 24" monitors.
I got a XFX 5870
I have also ordered the dell Display port to Dual link DVI Active Adapter. I had to do this because my monitors do not have a DisplayPort.

Ok now on to my question.

Now couldn't ATI have shared the HDMI port on the card with the DisplayPort instead of sharing with the DVI port. It seems like many people are having to order one of these expensive adapters.

I don't know if this is even possible but just thought about it and wondered why they did not do this instead. Then they could have just put a switch or toggle to select either HDMI port or Display Port on the card itself. You would think this would then tell the card that ok 3rd display is going out from the display port, or HDMI port what ever the switch was set on. If it was going out the HDMI port then we could just have used a passive adapter HDMI to DVI or just straight HDMI.

My whole understanding of this was just the limitations of the actual Display Port. Not the card itself. Please share your understanding or thoughts about this.

KryptoNyte · Post by **KryptoNyte** » 01 Dec 2009, 01:59

Because DVI and HDMI technology have very similar hardware requirements, which allowed them to cut $$$ and space on the video card by isolating the displayport as the third option. Displayport has little likeness to the DVI/HDMI.

Post by **BHawthorne** » 01 Dec 2009, 03:28

HDMI is more or less a repackaged DVI. DP is a whole new thing. The archetecture behind it is different.

It's like you have 3 people, one American, one Brit and one Chinese and then you ask the Brit why he can't speak Chinese. :lol:

bowenac · Post by **bowenac** » 01 Dec 2009, 03:59

Yea thats what I figured but in that case why not just go all HDMI. The HDMI port looks to be about the same size as Display Port. Why even add the Display Port at all.

Post by **suiken_2mieu** » 01 Dec 2009, 05:18

it's an added value solution. Plus ATI has been adding all the feature of HDMI into DVI for a while. You can use the DVI ports and an HDMI adapter and still run sound through it.

DP doesn't require clock signals to be produced, hence 1 less ASIC to put on the board, hence less money to dish out. Eyefinity wasn't the focus of the 5800 series cards, we on the other hand pretty much took it to be, so as were mad they look at us and say what, "we added it because it was cool." Basically.

whismerhill · Post by **whismerhill** » 01 Dec 2009, 08:17

Yea thats what I figured but in that case why not just go all HDMI. The HDMI port looks to be about the same size as Display Port. Why even add the Display Port at all.

and then what ?
add two HDMI=>DVI adapters for each and every card ? :roll: ;)

DVI is more present on the PC consumer market than HDMI !
whereas HDMI is more present than DVI on the TV consumer market, but this is irrelevant here.

bowenac · Post by **bowenac** » 01 Dec 2009, 08:23

[quote]Yea thats what I figured but in that case why not just go all HDMI. The HDMI port looks to be about the same size as Display Port. Why even add the Display Port at all.

and then what ?
add two HDMI=>DVI adapters for each and every card ? :roll: ;)

DVI is more present on the PC consumer market than HDMI !
whereas HDMI is more present than DVI on the TV consumer market, but this is irrelevant here.

Yea exactly because then we could by a $5 adapter instead of a $100 Active one. Makes more sense they would not have to add these adapters with every card they are easily available and cheap.

Post by **BHawthorne** » 01 Dec 2009, 15:14

That same arguement was regurgitated many times around here over a month ago. The reality of it is the design of the card can only have 2 legacy timing clocks in it, and not add in more without a major reworking. I argued this even before the cards were on the street. My arguement is that 6 Mini-DVI or 6 HDMI ports would fit just fine in any 5000-series back port plate. The plate isn't the issue, it's the design of the electronics required to push those ports that is at issue. Basically, it's not cost effective for AMD to screw with a redesign for the benifit of our niche market. To paraphase them, the enabling tech in all of this is DP and nothing else.

bowenac · Post by **bowenac** » 01 Dec 2009, 16:27

Ok I get what your saying now. And I am new so didn't see that argument a month ago haha. But just to throw it in there maybe it would not be such a niche market if there was an easier solution to all this. I imagine it turns people away knowing they either have to buy a new monitor with DP which there are not very many on the market. Or the $100 adapter. I just don't understand what these cards are marketed towards I guess. I was assuming Eyefinity was a big part of there market. And not just for gaming. But arn't these cards mostly targeted towards the gaming market, didn't they know this would be a big thing. I think they should have already been looking into making a cost effective adapter. I heard they are doing that right now.

Post by **Gilly** » 01 Dec 2009, 17:00

I suppose in the future we will see multiple mini DP connectors.

I mean... just at the moment, there are many ways that ATi COULD of improved the design. You could of had a multiple slot card with 3x DVI, 3x HDMI, 3x DP and 3x VGA. But they decided to go with tried and tested 2x DVI with 2 other ports, one of which is becoming more common, the other is just in its infancy with PC teritory.

Its about time we got some new sockets, HDMI is fine for HT systems but DVI is just bulky and heavy connector, far too much like a Scart cable for my liking. If ATi had its way and could control what screen manufacturers put on their screens, Im sure things would be a little different than they are now.

But it is how it is!!! Unfortunatly for some!

bowenac · Post by **bowenac** » 01 Dec 2009, 17:05

So would this not be possible if they just went with HDMI instead. Why not just make it with 2 DVI and 1 HDMI with none of them shared. How can this be possible with DP but not with HDMI. I guess I just don't understand why they didn't just use 2 DVI and 1 HDMI. Or 3 HDMI ports. And get rid of the DP all together. Just about every monitor has a HDMI port now. And if they don't a HDMI to DVI adapter they are about $5.

Greg Ellis · Post by **Greg Ellis** » 01 Dec 2009, 17:24

So would this not be possible if they just went with HDMI instead. Why not just make it with 2 DVI and 1 HDMI with none of them shared. How can this be possible with DP but not with HDMI. I guess I just don't understand why they didn't just use 2 DVI and 1 HDMI. Or 3 HDMI ports. And get rid of the DP all together. Just about every monitor has a HDMI port now. And if they don't a HDMI to DVI adapter they are about $5.

It's not just about connector choices, there's a limitation in the hw design. The 5000 products support a maximum of 2 legacy outputs. Legacy being DVI, HDMI, VGA, Component, whatever you like. So you can run DVI + DVI, or DVI + HDMI, or HDMI + HDMI, or VGA + DVI - any combination of two.

Most prior products are exactly the same - they support a max of two legacy outs.

On top of those two legacy outs, the 5xxx boards add DP ports. You can have as many DP ports as you like, up to the max outs supported by the chip (max is 6, for 58xx, I believe).

If you want to use one of those DP outs to drive a legacy monitor, you need an active dongle - i.e. a piece of h/w that interfaces with the graphics board as if it were a DP monitor, and then actively translates the DP content to drive a legacy display, generating all of the required clocks and signals, etc.

It doesn't have to be a $100 active dongle. It could be a $30 DP to VGA. Or some other design. But it does need to be active, because the board can only support two legacy displays, not three or five or eleven. Everything beyond those two is DP only.

bowenac · Post by **bowenac** » 01 Dec 2009, 17:28

Ok thanks for clearing that up. That was a good explanation. It doesn't matter I already ordered the adapter anyway haha. Was just wondering why this and why that.

Post by **BHawthorne** » 01 Dec 2009, 17:47

It's a design limitation of how the electronics that regulate the signal timing works. DP has no such clock limitions by design, but with DVI and HDMI and whatever else that is labeled "legacy", each port needs it's own dedicated clock hardware. DP, on the other hand, has a single new design of clock that is shared by all the DP ports on the card by design. It's a major archetecture change, hence the label of "legacy" for the older port designs. "Legacy" ports require dedicated clocks, one per port, while DP shares a single clock for all it's ports.

Post by **Gilly** » 01 Dec 2009, 22:21

I suppose a more elegant solution would of been if ATi gave each card an option of an adaptor bundles with the card. Although, as I type this, something seems to stick in my head that there might be something like this planned.

Dave Baumann · Post by **Dave Baumann** » 01 Dec 2009, 23:25

But they decided to go with tried and tested 2x DVI with 2 other ports, one of which is becoming more common, the other is just in its infancy with PC teritory.

The point it was to offer the same level of support as the previous generations (via DVI) and extend the capbilities with DP. For many of the users that have 2 panels then they can take the extension just by buying a new DP panel; that may not be many from here though as quite a few from this particular site are moving from 3 DVI to Eyefinity.

Dave Baumann · Post by **Dave Baumann** » 01 Dec 2009, 23:33

"Legacy" ports require dedicated clocks, one per port, while DP shares a single clock for all it's ports.

I'd posit that the term "legacy" stems from what interfaces have active development paths; of the many display outputs found on a graphics adapter only two have active development communities and roadmaps going forward - DP and HDMI.

DP takes off from where DVI left off with VESA, and is a license free interface developed specifically for the PC community. HDMI is developed off one of the legacy standards, has royalties associated with it and is being primarily developed for the CE community and as such may add featured that make little sense for PC's.

Post by **Gilly** » 02 Dec 2009, 00:07

The point it was to offer the same level of support as the previous generations (via DVI) and extend the capbilities with DP. For many of the users that have 2 panels then they can take the extension just by buying a new DP panel; that may not be many from here though as quite a few from this particular site are moving from 3 DVI to Eyefinity.

I worded it very badly, what I meant was something along the lines of:

2x DVI because it works and most people will have DVI screens, HDMI for HT applications, and DP for future proofing.

My personal use for eyefinity would be somewhere along the lines of what was possible before, so I wouldn't care for 3 monitor span, maybe 1 huge screen for gaming and then another for Firefox, Foobar etc etc, so for me, what the design constraints are do not matter for me one bit. I will buy what I want, and it will work :P

SunSp*t · Post by **SunSp*t** » 02 Dec 2009, 10:44

Yea thats what I figured but in that case why not just go all HDMI. The HDMI port looks to be about the same size as Display Port. Why even add the Display Port at all.

The answer isn't as simple as it might appear. BTW I haven't read the entire thread so this may all be addressed by others. I just don't have the time to read every post, so please forgive any duplication of answers...

The whole DVI-HDMI similarity is one thing (I see BH and others understand that).

The other (and I thought I mentioned this somewhere earlier...) thing is that HDMI has some serious issues which makes it much less desirable than DP:

[list]HDMI's resolution is essentially capped at 1920H 1080V 60Hz.
Each HDMI output carries a licensing fee.
We could spec a mini-DP connector, but not a mini HDMI coonector.
HDMI acceptance at EF inception was very, very poor, even in consumer TV.
HDMI cables have been pretty expensive.
HDMI cables are thicker, less flexible than DP's.
HDMI requires independent clocks, which raises the silicon cost noticeably.
HDMI's max cable length is less than DP's.
DP was designed for built-in scaling, something HDMI was not built for.
I probably forgot a few.[/list:u]

It was pretty straightforward HDMI was not going ot be the interface of choice three years ago. Would I have made a different decision knowing what I know now? No. DP is still the best choice for all of us.

SunSp*t · Post by **SunSp*t** » 02 Dec 2009, 10:47

DP takes off from where DVI left off with VESA, and is a license free interface developed specifically for the PC community. HDMI is developed off one of the legacy standards, has royalties associated with it and is being primarily developed for the CE community and as such may add featured that make little sense for PC's.

And I see DaveB has addressed much of the same stuff (like I said I don't have the time to read all these threads...).

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