Tripple channel memory on 790i ultra

My entire text got reduced to a few lines in the end.. *sigh*

So, based on the assumption that CPU-Z is in fact wrong and I am now running the 3 sticks in single channel, how much of an increase in bandwidth can I expect from removing 1 stick and then running in dual channel?

I use this computer for heavy games such as Crysis Warhead and I hear memory bandwidth is extra important when dealing with heavy graphics and anti-aliasing.