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<topic xml:lang="en-us" id="ts_host-freq-boost">
  <title>Performance Variation with Frequency Boosting</title>
  
  <body>
    <p>
        Many multicore processors support some form of frequency
        boosting, which means that if only one core is utilized, it can
        run possibly 50% faster or even more than the rated CPU
        frequency. This causes measured performance to vary somewhat as
        a function of the momentary overall system load. The exact
        behavior depends strongly on the specific processor model.
      </p>
    <p> As a consequence, benchmarking on systems which utilize frequency boosting may produce
      unstable and nonrepeatable results. This is especially true if benchmark runs are short, of
      the order of seconds. To obtain stable results, benchmarks must be run over longer periods of
      time and with a constant system load apart from the VM being tested. </p>
  </body>
  
</topic>
