HD5850 Crossfire PCI-E Lanes bottleneck

I am trying to decide on a motherboard right now with a bit of futureproofing in mind. I have an HD5850 and it's fantastic. However, I am getting a new motherboard and I am currently considering a Gigabyte GA-H55M-S2H:

There is a good chance I will pick up a second HD5850 in the future for Crossfire. Will the x4 lane bottleneck the Crossfire?

I've read the "PCI Express And CrossFire Scaling: Is P55 Good Enough?" article that pitches the P55 (x16+x4) against the X58 (x16+x16) with two HD5870 cards. Based on the article there appears to be very little difference for the two-card Xfire configuration so I am assuming my lesser HD5850s should see even less of an impact. Is this assumption correct and the motherboard I am considering should not bottleneck?
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More about hd5850 crossfire lanes bottleneck
  1. The 4x lane will seriously bottleneck the second HD5850.
  2. Going from 16/16 to 8/8 is a tiny performance loss for powerful cards (5870 for example) the weaker the card the less an issue this is.

    4/4 will be a much more notable bottleneck for powerful cards, and while the 5850 is weaker than the 5870 it will suffer.

    I have to admit, I am curious as to the effect of 4/4 on a weak card such as the 5770 - would it being 4/4 be the equivelant performance loss of a 5870 dropping to 8/8?
  3. 8x/8x is fine it's what I use and the performance is great. The x4 lane is crap, but that's not really an issue here.
  4. Ohh, thanks for the replies everyone. So I should definitely avoid a x4 lane but x8/x8 lanes should be fine?
  5. yep.
  6. Any cheap mobos that support x8/x8? It seems Asus makes a few but they're all relatively expensive.
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