Benchmarking is measuring up how something compares to a set standard. For PCs, you can benchmark how fast your system does word processing or computation or how well it can display graphic images. You can go to
www.madonion.com to get some benchmarking programs. They simulate a game running or someone doing intensive word processing, measure criteria and then compare it to a base system. The results are in some kind of score or frames-per-second count. You can then see how well or bad it does against a comparable system. Great to see if you want to tweak anything. Benchmark it again to see if you were able to make improvements. Have fun!