Serious CrossFire Limitation

[Major_A]

Earlier today I was given information regarding ATI’s upcoming Crossfire technology that, at first, I passed off as so ridiculous it couldn’t possibly be true. However, after having the information verified from several very reputable sources I’ve decided it would be a disservice to keep this information private.

As many are aware by now, ATI’s Crossfire technology uses an external link to connect the Master and Slave cards together (it's sort of like a 3-headed dongle with DVI connectors at the ends). What’s not generally known is that the backbone for this setup is a Silicon Image SiL 1161 chip which is installed on the X8-series Master cards. The SiL 1161 is there to receive output passed over the external link from the Slave card in the Crossfire setup and pass it on to the Master card.

Sounds decent on paper and everything, but if you check out the specs for the 1161 on this page you will see that it is limited to single-link TMDS @ 165MHz. This means that the max 3D resolution for any X8-series Crossfire setup is 1600x1200 @ 60Hz. That means no high-res Crossfire gaming beyond 1600x1200, no 1600x1200 at a flicker free refresh rate, and no widescreen 1920x1200.

How can a technology so clearly aimed at enthusiast gamers have a limitation like this? High-resolution flicker free gaming is one of the primary benefits a multi-graphics setup like Crossfire should offer entusiasts but, somehow, ATI managed to mess that up completely.
http://www.rage3d.com/index.php?cat=75#newsid33828812

All the people who voted Crossfire in the other poll will this affect your decision to buy this setup?

[Ugly n Grey]

I won't believe any of it until I see it...actual reviews by reputable sources. And neither should all of you...

[Major_A]

I agree completely. Let's say it is true, would it affect your purchase decision?

[cadaveca]

You bet it would. 1 card is generally enough for 1600x1200...at least overclocked x850, anyway, in most games. The only reason i would go crossfire was for 20" applecinema...

[eva2000]

i don't like widescreen res and only use 1600x1200 LCD mon, so seems fine for me.. but can see why some folks will be upset

[Frisch]

Yes, it would inflict on my decision, and as stated, it would seem rather "dumb". The main purchaser would be a highend, high resolution, big screen maniac, whit a major PSU replacing his heart. Pumping the machine beyond what Lance Amstrong did at TDF. If ATI dont know who buy what and why, it would be a shame. But at my age, life has so much else to offer, so let's just hope for the youth, that it's a rumor.

[Vapor]

Hmmmm...that means 1920x1200, which I would *prefer* to run at in not possible, but 1600x1200 is also plenty nice. Is this a factor in my purchase? Absolutely. Is it going to stop me from buying it? Doubtful, maybe delay it a week or so :D

[hixie]

I doubt ATI would make such an obvious mistake, and even if they did im sure they will do something about ASAP.
Crossfire is on my list of upgades, and i do plan on buying a 20" apple widescreen.

[stuka666]

Being this true... yes it would affect my purchase decision..

[[XC] leviathan18]

DVI

Short for Digital Visual Interface, a digital interface standard created by the Digital Display Working Group (DDWG) to convert analog signals into digital signals to accommodate both analog and digital monitors. Data is transmitted using the transition minimized differential signaling (TMDS) protocol, providing a digital signal from the PC's graphics subsystem to the display. The standard specifies a single plug and connector that encompass both the new digital and legacy VGA interfaces, as well as a digital-only plug connector. DVI handles bandwidths in excess of 160 MHz and thus supports UXGA and HDTV with a single set of links. Higher resolutions can be supported with a dual set of links.
DVI

Short for Digital Visual Interface, a digital interface standard created by the Digital Display Working Group (DDWG) to convert analog signals into digital signals to accommodate both analog and digital monitors. Data is transmitted using the transition minimized differential signaling (TMDS) protocol, providing a digital signal from the PC's graphics subsystem to the display. The standard specifies a single plug and connector that encompass both the new digital and legacy VGA interfaces, as well as a digital-only plug connector. DVI handles bandwidths in excess of 160 MHz and thus supports UXGA and HDTV with a single set of links. Higher resolutions can be supported with a dual set of links.

i was keeping that for the LCD buyers guide but i think it should be posted here.... i think the bandwith is pretty low...

now they should used HDMI for that interface

HDMI is fully backward compatible with PCs,displays and consumer electronics devices incorporating the Digital Visual Interface (DVI) standard. Both HDMI and DVI were pioneered by Silicon Image and are based on TMDS®, Silicon Image's powerful, high-speed, serial link technology. HDMI supports standard, enhanced, or high-definition video, plus multi-channel digital audio on a single cable. It transmits all ATSC HDTV standards and supports 8-channel digital audio, and with 5 Gbps of bandwidth

HDMI is two links of DVI with sound... channels and the bandwith is greater for high resolution....

this factor limits the perfomance of the plataform as we can see right now nvidia to use the power of sli with 2 7800gtx have to use hihg res with all the candy eye on to throw more stress to the GPU and less for the cpu.....

[craig588]

No. I don't care how it looks on the monitor as long as a scene is accurate. 10x7 is all I need untill Futuremark adopts something higher.

[pythagoras]

Whats wrong with this thread????

Regards

John.

[BRiT]

Crossfire is capable of doing 1920x1200...

http://www.theinquirer.net/?article=26228
However, you will be able to use 1920x1200 but you will be limited to 52Hz only. Bothc cases are fine for all TFT users as 60Hz on those displays by some miracle looks very good.

[Ugly n Grey]

You guys talk about resolutions I can't even see...wow...way too tiny little stuff on the screen...

[slider99]

Ofc This Affect My Purchase Decision. Going in for the big $$$ I wouldn't want to miss out on the 100 FPS+ LCD gaming!

[sideeffect]

Heh well 60 hz causes me headaches after a few hours gaming. It also means you cant see more than 60 fps at 1600 x 1200 because you can only see as many frames as the refresh rate allows.

This will mean a single card at 1600 x 1200 at 90 hertz will look better than a crossfire setup and even though the fps would be less it would seem like more :P

So if this is true. No i would never buy a crossfire till they fix it.

[Major_A]

Whats wrong with this thread????

Regards

John.
What do you mean?

*Rage3D was right and wrong at the same time*
Turns out 1920X1600 @ 52 Hz is also an option. So they only got half of the equation, guess that's 50% or a big fat F.

[Ugly n Grey]

What's wrong with the thread is that it's supposition based off research of a chip in an unreleased product.... be nice to see a review... I'm so tired of thinking about it...

[Major_A]

True, I know Anandtech is now under NDA, so I am assuming that other review sites are too. Maybe we'll see some actual numbers in the next few weeks. Hopefully when they are reviewing the X1800 they can double up and get some Crossfire numbers in there too.

[Arkangyl]

even if those resolution limitations are somehow not true, the ATI chipset itself has made me change my mind and want SLI over AMR. no SATA II, crappy USB.. sorry, not impressed. And it will probably still take a rev or 2 to get it right, like nVidia.

Sorry ATI, but I need my PC for more than framerates at times and that ish dont fly

[ingentingmendeg]

i highly doubt this. but it can be atleast 1600x1200 @ 85Hz. 60Hz will just give me a Headache. i mostly play my games at 1280x1024 anyways with everything maxed and looks beutiful. so ill still proboly get crossfire and play at 1280x1024. but will it be able to handle 85Hz at 1280x1024? it should right? and another thing, i dont get why people are complaining about it can only handle 1600x1200. most people have moniters that go up to 1600x1200 anyways. but im disapointed about the 60Hz thing at 1600x1200.

[Major_A]

What if alert....
i highly doubt this. but it can be atleast 1600x1200 @ 85Hz. 60Hz will just give me a Headache. i mostly play my games at 1280x1024 anyways with everything maxed and looks beutiful. so ill still proboly get crossfire and play at 1280x1024. but will it be able to handle 85Hz at 1280x1024? it should right? and another thing, i dont get why people are complaining about it can only handle 1600x1200. most people have moniters that go up to 1600x1200 anyways. but im disapointed about the 60Hz thing at 1600x1200.
Ok so I've seen rumors (yes they are just rumors) that the Crossfire motherboards are going to cost $250ish.
The master card for the X850 is supposed to retail at $550.
So you just spent $800 to play at 1280, that seems like a huge waste to me. If you are only planning on 1280 resolutions then a singe card setup is the way to go.