I'm tight on budget. I saw the Samsung B2230 which was right for my budget
I have the graphics card MSI 6870 for gaming exclusively like crysis. etc... I want to upgrade the monitor for the new graphics card to work perfectly.
I think you are misunderstanding the term 'bottleneck'.
Time to use a cliche, the chain is only as strong as the weakest link. Think a freeway with several lanes, and then for some reason, the lanes reduce to a fewer number, The traffic backs up because of the choke point. THAT is why some graphic cards experience slowdowns, the data flow is slowed somewhere in the path from cpu to display.
A bottleneck is essentially the slowest part of the system that can bring down the overall performance.
Suppose you built a computer with the best parts you could find (i7 CPU, DDR3 triple channel RAM, the fastest solid state drive) but paired it up with an embarrassingly old 7600 GT graphics card. The GPU would be the bottleneck.