Serious CrossFire Limitation

Dragunov · Sep 16, 2005, 04:57 AM

Quote:

Originally Posted by Ratchet

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.

Seen this on rage3d, posted by site admin

Greetz

Dragunov

The_Neon_Cowboy · Sep 16, 2005, 05:31 AM

"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."

hard to say, the slave card sends it's 50% of the info to the master card
via the SiL 1161 but then the outpout is done by the master card.

WE'd have to wait and see..

(I don't understand the chip says it supports)
Maximum Resolution: UXGA (1600 x 1200)
Bandwidth: 25 to 165 MHz

so 165htz @ 1600X1200 is the max the chip handles
and it only has to handles 1/2 the data, the data from
the slave card...

I'd have to say I'm confused to say the lest on this topoic...

H3X4D3C1M4L · Sep 16, 2005, 07:58 AM

If they'd just use a dual link card they could do 2048x1536 @ 85 Hz which is more than anyones monitor really supports (excluding uber CRT's)

deekey777 · Sep 16, 2005, 08:15 AM

Quote:

Originally Posted by The_Neon_Cowboy

"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."

hard to say, the slave card sends it's 50% of the info to the master card
via the SiL 1161 but then the outpout is done by the master card.

WE'd have to wait and see..

(I don't understand the chip says it supports)
Maximum Resolution: UXGA (1600 x 1200)
Bandwidth: 25 to 165 MHz

so 165htz @ 1600X1200 is the max the chip handles
and it only has to handles 1/2 the data, the data from
the slave card...

I'd have to say I'm confused to say the lest on this topic...

For me this "sensation" is a storm in a teacup.
http://www.hardware.fr/articles/573-...sentation.html

It's known since May 31st, that this evil SiL 1161 is on the master card.

dipstick · Sep 16, 2005, 11:54 AM

There's no way ATi could screw it up like this lol

Sandok · Sep 16, 2005, 11:56 AM

Very true