Widescreen Gaming Forum

This is why I've decided not to go with the ATI cards...

I was considering them as a solution to my multi monitor woes, but currently I have Tri-SLI GTX260s, so a single 5870 would be a downgrade, and I'd prefer 3 5870s to a 5890 or whatever (Damn things are long, plus Tri-whatever seems to scale better than Quad-whatever, for ATI and nVidia, IMO)

HOWEVER... if ATI can fix this, maybe I'll consider them eventually if my attempts to get my Mview box working continue to fail. After all, Eyefinity should scale better than the Nvidia equivalent IN THEORY due to all 3 monitors being on the one card.

So yeah... you listening ATI? You're losing customers over this. Oh, the lack of custom crossfire profiles is a deal breaker too.

"The core issue is the fact that the dedicated CrossFire interconnect
used for passing completed frames between cards has "only" enough bandwidth
to sustain a 2560x1600 display resolution. Even three 1080p displays will
exceed its capacity."

If this is true, then what hardware are they using when they demo 6 x 30" displays?

Just the one Eyefinity6 card presumably. I don't think Eyefinity works with one display group across multiple cards. Not yet anyway :)

The limitation in the Crossfire link (if true) is why Crossfire Eyefinity scales so badly. That is the point... 3 1080p monitors generate too much bandwidth for the Crossfire cable to handle. That's how I interpret the statement. It's much slower to send the data via the PCI-E link. The 5970 doesn't have as much of a problem with this as it's chips are physically closer and connected via a bridge chip, so they can 'talk' more easily.

you left out the next part of the article:

"Using PCIe works, but it can limit performance scaling somewhat—don't expect to see the near-linear scaling one might get out of a dual-card setup in the right game with a single display. That's not to say mixing CrossFire with Eyefinity won't be worth doing. Based on AMD's performance estimates, frame rates could improve between about 25% and 75% when adding a second GPU with a 12-megapixel, six-monitor array."

i don't know about the 5970 + 5870, but this seems to indicate that 5870 in CF will net some gains. It is good that I came across this though as I was about to go out and drop the cash on a second 5870. Think I will wait for some more benchmarks and newer drivers.

? is how could they not test and know this when they made the 5870 card? Why didn't they fix the Crossfire bridge issue then?

the more i think about it, you must only be referring to quad-fire (2x5970).

Because, I just came across some more benchmarks which shows huge gains going from 5870 to 5870x2.

http://www.legionhardware.com/articles_pages/metro_2033_performance_guide,10.html

My apologies if i posted a response in ignorance to your original ?.

TF

For what it's worth, my 5870 E6 cards in CFX work just fine. I have them connected with two CFX links. Maybe that is solving the bandwidth issue.

For what it's worth, my 5870 E6 cards in CFX work just fine. I have them connected with two CFX links. Maybe that is solving the bandwidth issue.

I'm willing to try anything ... I just attached a 2nd CFX link, I'll try firing up CFX on BC2 again @ 3x30".

the more i think about it, you must only be referring to quad-fire (2x5970).

Because, I just came across some more benchmarks which shows huge gains going from 5870 to 5870x2.

http://www.legionhardware.com/articles_pages/metro_2033_performance_guide,10.html

My apologies if i posted a response in ignorance to your original ?.

TF

Yeah, they show huge gains @ 1680x1050 :doh

crap... you are right. my head is not screwed on right.

guess i will wait a bit longer before getting that second 5870.

[quote]For what it's worth, my 5870 E6 cards in CFX work just fine. I have them connected with two CFX links. Maybe that is solving the bandwidth issue.

I'm willing to try anything ... I just attached a 2nd CFX link, I'll try firing up CFX on BC2 again @ 3x30".
What cards are you running, two 5870's?