I have my current system and was planning on upgrading it, but I don't have time to do a lot of gaming so I have dropped plans to upgrade until now. Next quarter I will begin taking C++ classes and wanted to know if I should upgrade my CPU to an i7, i5 or just keep my slow and faithful AMD chip. Will an upgrade make all that much of a difference in performance when compiling?
An upgrade will only make a large difference if dealing with large programs. If you're dealing with programs <1500 lines (off the top of my head, ballpark figure) you won't notice any difference. You could always upgrade if you notice it takes more than a few seconds to compile. My school's computing rooms have PCs based on first-gen i3s, and still compile almost instantly.