How many requests was that?
Ultimately, if you have very fast disk IO and a very slow network connection to your memcache(d) server then it's possible.
I believe it was 5000.
Sorry, I can't answer your question, but a question to ask you. Every time I run the test performance it always shows that Store not ready, or Invalid plugin. What is the reason? What have you done to make them enable and work normally.
Have you configured this plugins in the 'cache administration' screen? They are not enabled by default.
To add to what Howard said, even if you configure the cache backends in the primary caching configuration screen, to be able to run benchmarks you have to configure the Test Servers under the Caches Stores dropdown
Is there documentation on how to read these outputs when running the test? Is a higher number better or worse? What do the numbers presented actually mean?
Lower (faster) is better.
It's all relative. The file cache results are the first place I look if a Moodle's page load times are slow. For the default screen, there are normally several zeroes after the decimal point if the cache is fast (i.e. quick local disk working properly). Poor disk IO or using slow shared storage will produce results a lot higher.
Are these measurements in milliseconds? Would it be possible for a legend for these kinds of charts?