Why is an identical machine getting a different score than mine?

If you notice a system has a markedly different performance value and score than the same hardware of others like it, any of these components may have affected the result:

• Can your computer be cooled sufficiently? 
  Both the ambient temperature and the temperatures inside the case can influence the performance values. If the processor gets too hot, you will get different values than a processor with good cooling.
• Can your power supply provide enough power?
  If a power supply is too weak or has fluctuations in the output power, it can affect the GPU and thus, in addition to poorer values, also the stability of the graphics card.
• Is the CPU / GPU overclocked?*
  While most processors can tolerate overclocking, if the cooling of the system and the performance of the power supply aren't adequate, both points above come into effect.
• Did you run the test for less than 10 minutes?
  Tests should run for 10 minutes on account processors heat up over time, which in turn affects their speed. Performance values may be higher for shorter tests, but if the test runs for 10 minutes, an average value is calculated which then represents a more accurate performance measurement.
• Is your graphics card driver up to date? 
  Since manufacturers ensure that drivers receive performance improvements and bug fixes as quickly as possible, GPU drivers can quickly become outdated. For Windows users this means downloading the driver directly from the developer's website; for Mac users this means downloading the latest macOS version.

More technical information about Cinebench can be found here.