kdmaris, can you post the link to what you've found? You can't just add a third stick to the 2x4GB kit to get triple channel memory; you must buy a triple channel set. If you do that, you won't see the same performance as you would with an actual triple channel set.
Two things - the first is that you're definitely overpaying for that type of RAM when you can get the same thing on Newegg for $60 or less.
The other is that you're using an X58 system - it will have problems if you try to use dual channel RAM on a triple channel system. You're actually looking at 12GB (3 x 4GB) for that type of system. Here's the same thing in a triple channel configuration: