bottlenecking is pretty much when one part of the system limits the whole system.
Like for example, if you got an quad core, but you only have 512mb of ram. You cant really use the quad core to the full extent due to the 512mb, so then in order to use the quad core to its full potential would be to upgrade to 2gb or ram.
Another example would be if you had a really great system able to run everything all fast, but you are using Onboard video, and when you play games, you cant have good graphics, and get bad FPS, and lags a lot. Reason is because the onboard is bottlenecking the whole system, so then you cant use the system to the full extent when playing games till you get a new graphics card. This kind of applies to monitors too, like if you got one that displays 1024x764, and you got like the 4870X2, you cant really use it to the fullest because the monitor doesnt require that much power from the graphics card.
can you post the link of the motherboard you have?
EDIT - the 1200mhz of ram seems pretty expensive, and not very popular.
may i ask why you want to get 1200mhz? It might be cheaper and better if you go with the 1066mhz if your mobo supports it.
EDIT2 - doing some research, it says it only goes up to 1200mhz with EEP, which i think its something to do with SLi/Crossfire.
I am not really familiar with this kind of stuff.
mayber the eVGA support center can help you further since its their product.
http://www.evga.com/community/chat/
but it seems like its out of service. Maybe try the message board.
sorry for not being much of help.