performer

A concise expression meaning "of adequate performance" without stretching to "high-performance" (especially since High Performance Computing has a specific meaning of its own). Unfortunately, in the modern language of hyperbole, terms like "adequate" and "acceptable" have negative connotations along the lines of "not really good enough but better than nothing". So, we, as an industry, have invented a jargon word "performant" to express the idea that a thing has a level of performance sufficient that you don't need to worry about it and can look for optimisations elsewhere in your system.