I hate this term as it's be blown WAY out of proportion.
A computer bottleneck occurs when one computer component holds back the performance of another computer component. In a CPU bottleneck, the CPU is running at 100% capacity and the GPU is left waiting for data from the CPU. In a GPU bottleneck, the CPU has data to transfer to the GPU, but the GPU is too busy still processing the latest set of commands from the CPU.
The plain and simple answer here is this:
Unless you are pairing a low-end processor with a high-end graphics card, don't worry about it. Any performance loss is minimal and not likely noticeable.
Unless you are pairing a low-end graphics card with a high-end CPU, don't worry about it. The graphics card can only...