5850 from PCI-E 8x

[grandpatzer]

I have crossfire mobo M4A78-E.

You are supposed to use the bottom PCIE for 16x lane.

I need the PCI slots so I have to use the top PCIE 8x lane.

Will there be performance loss with one 5850?

 

[risqu3]

shouldn't be too much of a problem. You will know if you are bandwith capped or not if you start getting massive frame rate drops.

 

[FaRKle0079]

I need the PCI slots so I have to use the top PCIE 8x lane.

Will there be performance loss with one 5850?

It'll be negligible. IIRC, there was an article on Tom's showing that 8x vs 16x wasn't an issue.

 

[Ruffian]

It'll be negligible. IIRC, there was an article on Tom's showing that 8x vs 16x wasn't an issue.

Is there something that shows a crossfire at 2 by 8x versus 2 by 16x?

I was looking at a couple mainboards, and want to see how much gain I get by gettin two full channels.

 

[Meaker]

1-2% at most for single card operation.

Feel free to cry now.

 

[Cruiza]

1-2% at most for single card operation.

Feel free to cry now.

This. I've seen benchmarks backing this up, but I'm way too lazy to fish them out now.

 

[fochkoph]

Most benchmarks I've seen testing 8x vs 16x show only a few percentage loss in frames per second with the 5870. So considering the 5850 isn't as powerful I don't imagine there would be any performance loss.

TPU's Article with the 5870: http://www.techpowerup.com/reviews/AMD/HD_5870_PCI-Express_Scaling/