Quote Originally Posted by Helmore View Post
You have too high hopes for that CrossFire(X) sideport, this sideport has always been there since the X1950 Pro and it is nothing special so far. What else do you think those 2 golden fingers at the top of the card are for? That is simply the CFX sideport. They have been improving it gradually, but I don't expect miracles this time.

@zerazax: There won't ever be >2x scaling, not even when building a monolithic die with twice the processing units.
Then go tell that to Eric Demers, where I got that quote from. He by the way worked on R600 and RV770 probably as well, so I'd say he's quite a bit qualified to know what the heck the architecture is capable of.

And you've got it completely wrong. The CrossFireX Sideport is a PART of the chip. Look at this:

http://www.rage3d.com/reviews/video/...70-diagram.jpg
It's connected to the hub.

Also, take a look at the hub:

http://www.rage3d.com/reviews/video/...s/Hartog/8.jpg

Again, its part of the chip on the hub. The CrossFireX sideport was not part of R600's architecture layout nor R520/R580 when those gold fingers started appearing. Furthermore, the slide even states CrossFireX interconnect which is similar to that slide of R700 where it states "new GPU interconnect" or whatever.

Oh and just for effect, from anandtech's review (link)

The CrossFire Sideport

Although AMD isn't talking about it now, the CrossFire Sideport is a new feature of the RV770 architecture that isn't in use on the RV770 at all. In future, single-card, multi-GPU solutions (*cough* R700) this interface will be used to communicate between adjacent GPUs - in theory allowing for better scaling with CrossFire. We'll be able to test this shortly as AMD is quickly readying its dual-GPU RV770 card under the R700 codename.

One thing is for sure, anything AMD can do to assist in providing more reliable consistent scaling with CrossFire will go a long way to help them move past some of the road blocks they currently have with respect to competing in the high end space. We're excited to see if this really makes a difference, as currently CrossFire is performed the same way it always has been: by combining the output of the rendered framebuffer of two cards. Adding some sort of real GPU-to-GPU communication might help sort out some of their issues.
Or, how about extremetech (link)

This may be our first hint at what is new with the dual-chip "R700" product coming in a few months—these hubs may communicate between two RV770 chips in a fashion that is more efficient than in past multi-GPU boards.