There have been absolutely no improvements made in how SLI or Crossfire works. This occurred on my PC both before and after the patch:
http://i.imgur.com/kUbh3.png
Another user on another forum (well-regarded as somewhat of a haven for people focused on PC-based graphical performance) confirmed exactly the same was happening for them with nVidia/SLI:
http://forums.guru3d.com/showpost.php?p=4484507&postcount=568
"SLI still the same for me! Fckn hell, really regret buying this game."
Nothing has been fixed regarding SLI/Crossfire performance. At all. The only thing that's Most Wanted about this game is something to allow it to run properly on even top-of-the-range PCs, according to this post:
http://www.neogaf.com/forum/showpost.php?p=45592577&postcount=556
"Given that Criterion made it known in an interview with games.on.net that a 'modern quad core PC with an AMD Radeon 6000 series or NVIDIA Geforce 500 series can run the game with highest details settings' anyone using a videocard from the last 2-3 years should be able to run Most Wanted without issue. As c0Zm1c has frame rate issues with a GTX 690 and I'm reading people who have GTX 680 & 670 sli configs with frame rate issues plus ATI users encountering the same issue, it's fair to state it is Criterion who've screwed up. Does EA even care enough to fix the problem given console players are their main source of revenue?"
That's an nVidia GTX 690. Currently the going rate for that here in Australia is ~$1300AUD and it's still not enough to run this game at 60fps with the best settings.
I think someone has some work to do.