Is there a difference between and ? “Performance” feels like it's specifically about execution speed; “efficiency” could be about memory or disk space or other resources.

In any case, the four questions tagged must be retagged, to fix the spelling. Should they be retagged to or ? Should and be synonyms?

  • 2
    are these tags really useful? Jul 8 '11 at 22:44
  • 2
    @xenoterracide Yes, it's useful to easily search for questions that are about performance/efficiency, and performance has a few followers. What I don't know is if there's a need to distinguish between the various kinds of efficiency, or what the best name is. Jul 8 '11 at 22:48
  • I went ahead and retagged some of those.
    – tshepang
    Jul 9 '11 at 10:09

Well, I'm not too concerned either way, but I'll vote for making a synonym of


Efficiency is about appropriateness of resource consumption. Performance is about speed of execution. They are similar, but slightly different, concepts. Using the minimum CPU and memory to get a particular job done within the time constraints may be the most efficient way to do the job, but it won't provide the highest performance.

Most likely, people are tagging questions when they mean . There aren't that many real questions about efficiency.


Efficiency can be about memory usage, or power consumption, but performance can be used for that purpose too, while most questions are about speed of execution.

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