Zuhl3156
As I mentioned in another post and in a review by Guru3D the lighted version SLI bridges can and will work at the higher transfer frequency of the HB SLI bridge.
I think I remember Tom (mumble) of nvidia during the pcper livestream showing some slides that had the HB bridge with twice the data bandwidth of the old sli bridges. If I run accross that again, I'll post a link.
edit. the link has already been posted here.
https://www.youtube.com/watch?v=rO7pfttVAn0I just watched the beginning of that segment 3 times and its not 100% clear to me if the new HB bridge really can transfer more data than the LED bridge. He did say the HB bridge and LED bridge both work at higher frequency than the old cable bridge. He alluded to more bandwidth on the HB bridge though. Ie double the data lines. I'll admit there was a lot of hand waving just like at the product intro, that left me wondering what it was I just heard.
But I believe what I heard was HB bridge and LED bridge both the same speed. But HB bridge transfers more data at that speed which is important for higher res displays.
But I wouldn't bet my next bag of peanuts on what I think I heard.
Somewhere though there is a talk that lays out a HB bridge schematically and talks about what the additional data lines of the HB bridge really do for you.