Moo0 SystemMonitor is a freeware application which helps you to keep a watch over system resource usages of your PC. It currently supports 13 kinds of information including CPU, Memory, Network, and detailed HDD usages. Using this software, you may discover what is limiting your system performance in each occasion.
This freeware supports Vista as well and there is function that let you easily configure whether this software starts together on system boot or not. As shown in the image it gives information on 13 system processes like CPU usage, Memory, Memory swap, Hard disk, connections etc.
This application does not do any optimizations, but only shows which is causing low performance of system. Moo0 System Monitor is supported on Windows XP and Vista.