Instructions per second

Instructions per second (IPS) is a measure of a computer's processor speed. Many reported IPS values have represented "peak" execution rates on artificial instruction sequences with few branches, whereas realistic workloads consist of a mix of instructions and even applications, some of which take longer to execute than others. The performance of the memory hierarchy also greatly affects processor performance, an issue barely considered in MIPS calculations. Because of these problems, researchers created standardized tests such as SPECint to (maybe) measure the real effective performance in commonly used applications, and raw IPS has fallen into disuse.

The term is commonly used in association with a numeric value such as thousand instructions per second (kIPS), million instructions per second (MIPS), or Million Operations per Second (MOPS).

Thousand instructions per second

A thousand instructions per second (kIPS) is rarely used, as most current microprocessors can execute several million instructions per second. The thousand means 1000 not 1024.

kIPS is also a common joke name for 16 bit microprocessor designs developed in undergraduate computer engineering courses that use the text Computer Organization and Design by Patterson and Hennessy (ISBN 1-55860-428-6), which explains computer architecture concepts in terms of the MIPS architecture. Such architectures tend to be scaled down versions of the MIPS R2000 architecture.

Million instructions per second

Critics of the term refer to it by backronyms such as "Meaningless Indication of Processor Speed" or "Meaningless Information on Performance for Salespeople" or "Meaningless Integer Performance Spec". In Linux and UNIX circles MIPS are often referred to as bogoMIPS. MIPS are not comparable between CPU architectures.

The floating-point arithmetic equivalent of MIPS Million Instructions per second, is FLOPS, to which the same cautions apply.

In the 1970s, minicomputer performance was compared using VAX MIPS, where computers were measured on a task and their performance rated against the VAX 11/780 that was marketed as a "1 MIPS" machine. (The measure was also known as the "VAX Unit of Performance" or VUP. Though orthographically incorrect, the "S" in "VUPs" is sometimes written in upper case.) This was chosen because the 11/780 was roughly equivalent in performance to an IBM System/370 model 158-3, which was commonly accepted in the computing industry as running at 1 MIPS.

Most 8-bit and early 16-bit microprocessors have a performance measured in kIPS (thousand instructions per second), which equals 0.001 MIPS. The first general purpose microprocessor, the Intel i8080, ran at 640 kIPS. The Intel i8086 microprocessor, the first 16-bit microprocessor in the line of processors made by Intel and used in IBM PCs, ran at 800 kIPS. Early 32-bit PCs (386) ran at about 3 MIPS.

zMIPS refers to the MIPS measure used internally by IBM to rate its mainframe servers (zSeries and System z9).

Timeline of instructions per second

Processor	IPS	IPS/MHz	Year	Source
Pencil and paper (for comparison)	0.0119 IPS	n/a	1892	[1]
IBM System/370 model 158-3	1 MIPS	?	1972
Intel 8080	640 kIPS at 2 MHz	0.320 MIPS/MHz	1974
VAX 11/780	500 kIPS	?	1977
Motorola 68000	1 MIPS at 8 MHz	0.125 MIPS/MHz	1979
Intel 386DX	8.5 MIPS at 25 MHz	0.340 MIPS/MHz	1988
Intel 486DX	54 MIPS at 66 MHz	0.818 MIPS/MHz	1992
PowerPC 600s (G2)	35 MIPS at 33 MHz	1.06 MIPS/MHz	1994
Intel Pentium Pro	541 MIPS at 200 MHz	2.705 MIPS/MHz	1996	[2]
ARM 7500FE	35.9 MIPS at 40 MHz	0.897 MIPS/MHz	1996
PowerPC G3	525 MIPS at 233 MHz	2.253 MIPS/MHz	1997
Zilog eZ80	80 MIPS at 50 MHz	1.6 MIPS/MHz	1999	[3]
Intel Pentium III	1354 MIPS at 500 MHz	2.708 MIPS/MHz	1999
AMD Athlon	3561 MIPS at 1.2 GHz	2.967 MIPS/MHz	2000
AMD Athlon XP 2400+	5935 MIPS at 2.0 GHz	2.967 MIPS/MHz	2002
Pentium 4 Extreme Edition	9726 MIPS at 3.2 GHz	3.039 MIPS/MHz	2003
ARM Cortex A8	2000 MIPS at 1.0 GHz	2.0 MIPS/MHz	2005	[4]
Xbox360 IBM "Xenon" Triple Core	6400 MIPS at 3.2 GHz	2.0 MIPS/MHz	2005
P.A. Semi PA6T-1682M	8800 MIPS at 2.0 GHz	4.4 MIPS/MHz	2007	[5]
AMD Athlon FX-57	12000 MIPS at 2.8 GHz	4.285 MIPS/MHz	2005
AMD Athlon 64 3800+ X2 (Dual Core)	14564 MIPS at 2.0 GHz	7.282 MIPS/MHz	2005	[6]
AMD Athlon FX-60 (Dual Core)	18938 MIPS at 2.6 GHz	7.283 MIPS/MHz	2006	[7]
Intel Core 2 X6800	27079 MIPS at 2.93 GHz	9.242 MIPS/MHz	2006	[8]
IBM Cell one SPE	25600 MIPS (MFLOPS) at 3.2 GHz	8.0 MIPS/MHz	2006
IBM Cell one PPE	51200 MIPS (38400 MFLOPS) at 3.2 GHz	16.0 MIPS/MHz	2006
IBM Cell BE (1PPE + 8SPEs)	256000 MIPS (MFLOPS) at 3.2 GHz	80.0 MIPS/MHz	2006
SONY PS3 (1PPE + 7SPEs)	230400 MIPS (217600 MFLOPS) at 3.2 GHz	72.0 MIPS/MHz	2006
Intel Core 2 Extreme QX6700	57063 MIPS at 3.33 GHz	17.136 MIPS/MHz	2006	[9]
Intel Polaris Prototype *	1800000 MIPS (MFLOPS) at 5.8 GHz	310.4 MIPS/MHz	2007

* wiki java is unable to sort large numbers

See also

• FLOPS
• benchmark (computing)
• million service units (MSU)
• Peak MIPS
• Relative MIPS
• Dhrystone MIPS (DMIPS)