re: Looking to upgrade processor - advice sought

Doesn't matter what i3 you have. It's a Clarkdale for sure. Don't upgrade your CPU to another 1156 CPU. Waste of money unless you can get that i7 for like $75 and actually NEED it. The IPC is low compared to modern processors. Even a 6-core AMD (FX-6300) outperforms that i7 you linked. In fact, a $100 Haswell i3 outperforms that i7. For a home build, never, ever, ever build on the Intel platform with the intent to upgrade the CPU. By the time the CPU is worth upgrading, Intel will have changed sockets. In this case, they've changed sockets twice.

Take Hopeful Doc's advice if you don't have an SSD. If you do already have an SSD, collect some hard data on your CPU usage, as well as RAM, when you're running specific programs. Monitor temperatures to make sure nothing is throttling. Be absolutely sure it's the CPU bottlenecking your work. Too often, people see their PC underperforming and automatically assume it's the CPU.