Viewing Agents Workload
TeamCity provides handy ways to estimate build agents efficiency and help you manage your system:
The Matrix avialable at the Matrix tab on the Agents page provides you with a bird's-eye view of the overall Build Agents workload for all finished builds during the time range you selected. By taking a look at the build configurations compatible with a particular agent, you can assign the build configuration to particular Build Agents and significantly lower the idle time. This helps you adjust the hardware resources usage more effectively and fill the discovered productivity gaps. 
Select the time range and click Update to reload the matrix.
Click to navigate to Viewing Build Agent Details.
Total build duration during specified time.
Total build duration for particular build configuration, for builds that were run during specified time range.
Total duration of the particular build configuration builds that were run on the particular build agent during specified time period.
Build agent is compatible with the build configuration, but no builds were run during specified time range.
Build agent is incompatible with the configuration, or disconnected.
Build Agents' Workload Statistics
TeamCity provides a number of visual metrics, namely, statistics of Build Agents' activity and their usage during a particular time period. These information is available at the Statistics tab on the Agents page. 
your daily administration activities aimed at lowering your company's network workload
locating and eliminating the gap between the most frequently used computers and those which are often idle
reducing the cost of your hardware resources ownership