X16 x16 or x16 x8 x8 or x8 x8 x8 x8

[El_Capitan]

So I heard a rumor that x58 motherboards can only utilize up to 36 pipelines. Meaning that if someone had a board that supported x16 x16 x8 SLI or Crossfire, it would actually downclock one x16 to x8 in a tri-SLI or Crossfire set-up. Is this true?

In either case, what's better?

 

[cybot_x1024]

http://www.techpowerup.com/reviews/AMD/HD_5870_PCI-Express_Scaling/1.html

definitely having all the slots at x16 would best them all. though you cant fail to pay attention that x8 and x4 only have 2% and 5% perfomance difference respectively with x16.
therefore it comes down to SLI/CF scaling. 1 card, 2 cards, tri or quad? which scales better with the 2% in mind.

 

[mactronix]

I already knew that AMD/ATI cards wwere very good at this but would like to see the same tests done for Nvidia cards.

Mactronix