For those who build computers, we often use the term “bottleneck.”  Bottlenecks occur when one component of a system is woefully slower than the others.  Think of a computer like a chain .. its only as strong as its weakest link.
Computers 101
Basic info about computers, phones, tablets, and other technology
Differences in Speed Between Desktops and Laptops
Someone recently asked for recommendations for a new PC. For his needs, I said, "For a laptop, a Core i5, at a bare minimum. For a desktop, a Core i3 would be plenty." But why the difference? Shouldn't a Core i5 desktop have about the same...