I guess, at the end of the day, what you actually want when considering an upgrade is the stated processor type, and the current speeds. I.e. rather than upgrading an old processor, you may try a simple, and free, overclock before anything else. And a simple view of the memory installed is handy too. I'm not sure many BIOSes show you exactly how the memory slots are populated. And if they do it during POST, you need a photographic memory!
If you want to see a comparison of your machine against similar setups, then SiSoft Sandra is your lady. She will benchmark most areas of your PC, and you can then compare against pre-loaded benchmarks. I know that many people would see benchmarking as a sad hobby. Well, if the only driver is to push the performance of an already capable setup a little more, then it perhaps is sad, but a well rounded benchmark can identify any areas of your setup that aren't performing too well.