Editing Instructions per second (section)

{{Short description|Measure of a computer's processing speed}}
{{Use dmy dates|date=June 2023}} 
[[File:Computing efficiency, OWID.svg|thumb|400px|Computer processing efficiency, measured as the power needed per million instructions per second (watts per MIPS)]]

'''Instructions per second''' ('''IPS''') is a measure of a [[computer]]'s [[Central processing unit|processor]] speed. For [[complex instruction set computer]]s (CISCs), different [[Machine code|instructions]] take different amounts of time, so the value measured depends on the instruction mix; even for comparing processors in the same family the IPS measurement can be problematic. Many reported IPS values have represented "peak" execution rates on artificial instruction sequences with few [[Subroutine|branches]] and no [[Resource contention|cache contention]], whereas realistic workloads typically lead to significantly lower IPS values. [[Memory hierarchy]] also greatly affects processor performance, an issue barely considered in IPS calculations. Because of these problems, synthetic [[Benchmark (computing)|benchmarks]] such as [[Dhrystone]] are now generally used to estimate [[computer performance]] in commonly used applications, and raw IPS has fallen into disuse.

The term is commonly used in association with a [[metric prefix]] (k<!-- k (kilo) in lower case -->, M, G, T, P, or E) to form '''kilo instructions per second''' ('''kIPS'''), '''mega instructions per second''' ('''MIPS'''), '''giga instructions per second''' ('''GIPS''') and so on. Formerly '''TIPS''' was used occasionally for "thousand IPS".