Crossfire

[knyghtfall]

Was wondering if anyone knows if I need 2 connecting straps to crossfire my hd5770's. I have been looking around on the net at pictures and I see some with 2 and some with one. If only one is needed what slot is better to use or does it matter?

[ZekeTheSquirrel]

I was noticing the same thing. My pair of 5850's are currently using just one bridge, and the Crossfire functionality is certainly working. However, it would be interesting to know if using multiple bridges allowed for greater performance.

[knyghtfall]

Im guessing it is just for tri-crossfire but it would be nice to know ...fo-sho.

[cornelious0_0]

It's a little shady, ATI has said that the second bridge is used for later gen cards but there have been enough people run with either 1 or 2 bridges that have said it really doesn't matter. The performance difference is often as small as 2fps and some games actually act a little buggy with the 2nd bridge.

Try it with two if you've got it and leave it if everything works, try removing the 2nd bridge as an early troubleshooting step if something's acting up in game.

[DHS-Keith]

In our experience, only one bridge connector between two cards is needed to get full benefit of CrossFireX. The second connector on the cards is for connecting 3 and 4 cards together. I've never fully understood why the connectors are necessary to begin with since the PCIe standard is inherently a serialized point-to-point networking topology. Seems like the video card synchronization should be able to happen on the bus, versus through the bridge connectors. Here are some resources that may interest you:

http://en.wikipedia.org/wiki/Pci_express
http://en.wikipedia.org/wiki/ATI_CrossFire
http://game.amd.com/us-en/crossfirex_about.aspx
http://game.amd.com/us-en/content/images/crossfirex/CF_combo_chart.jpg

[cornelious0_0]

Thanks Keith, another great list of articles to add to the Info Hub once I get my a$$ in gear and re-prioritize my time.

[digitaljedi13]

Great info Keith, looking at putting a pair of 5870's in my machine at some point in the near future. Definitely have some good reading ahead of me.