nHancer is an alternative to nvidia's control panel and is far better suited to managing game profiles and their options.
One of the options available in a profile is the ability to display a SLI load balancing graph. You can enable this with nhancer.
Just set the option so that on "on" checkbox is ticked.
You can find the nHancer thread here: http://www.nvnews.net/vbulletin/showthread.php?t=82570