Triple-Channel and Dual-Channel or whatever will NOT boost performance in real-life applications such as Photoshop, games, Microsoft Word, etc.
But, if you're playing benchmarking software, it helps. Benchmarking softwares are meant for PC Enthusiasts, Extreme OCer(which want to win some titles, etc).

It won't affect performance if you throw in some random RAMs into your current setup.
But, it's not worth to do so. 2GB RAM mixed with 4GB RAM and 2000MHz mixed with other MHz, different CLs, etc. LOL.

For a PC Enthusiasts or OCer, setting up random RAMs is definitely WRONG. LOL.

For normal people, it's OK.