General

People areasking:"Can the Raspberry Pi 2 replace your desktop computer?" Well, it surely depends on the way you use your desktop computer. Basically, if you are a gamer, you won't be satisfied with this little Pi.To give practical results, we will benchmark the Raspberry Pi 2 and compare it to the other computer architectures, including not only previous model RPi but also architectures such as Intel Pentium III or Core i7.In Part 1, we are benchmarking the CPU, memory and bus. In the following days, we will publish Part 2, which will cover Java, OpenGL, Lan/Wifi and Multithreading benchmarks.The following benchmarks and other system's benchmark results are taken from Roy Longbottom'swebsite. In his website, there are numerous free benchmarks and reliability testing programs for processors, caches, memory, buses, disks, flash drives, graphics, local area networks and Internet.Raspberry Pi 2 System

It has a 900 MHz quad-core ARM Cortex-A7 CPU, 1 GB SDRAM and available connections like HDMI, 4 x USB, 40 pin GPIO and MicroSD card.The operating system we are using for these tests are Raspbian, based on Linux Debian.CPU is not overclocked.Whetstone Benchmark

The Whetstone Benchmark was the first general purpose benchmark that set industry standards of performance, particularly for minicomputers, and introduced in 1972. The benchmark produced speed ratings in terms of Thousands of Whetstone Instructions Per Second (KWIPS). In 1978, self timing versions (by yours truly) produced speed ratings, for each of the eight test procedures, in MOPS (Millions of Operations Per Second) or MFLOPS (Millions of Floating Point Operations Per Second), with an overall rating in MWIPS, mainly dependent on floating point speed.

Results below are for Raspberry Pi 2 running at 900 MHz. For comparison purposes, there are results of different Android based ARM CPUs and Intel processors running Linux.MWIPS : Millions of Whetstone Instructions Per SecondMFLOPS : Millions of Floating Point Operations Per Second

Dhrystone 2 Benchmark

The Dhrystone "C" benchmark provides a measure of integer performance (no floating point instructions). It became the key standard benchmark from 1984, with the growth of Unix systems. The first version was produced by Reinhold P. Weicker in ADA and translated to "C" by Rick Richardson. Two versions are available - Dhrystone versions 1.1 and 2.1. The second version, used here, was produced to avoid over-optimisation problems encountered with version 1, but some is still possible. Speed was originally measured in Dhrystones per second. This was later changed to VAX MIPS by dividing Dhrystones per second by 1757, the DEC VAX 11/780 result, the latter being regarded as the first 1 MIPS minicomputer.

VAX MIPS rating is the important value for us. Below is a similar combination of results as for the Whetstone Benchmark.Linpack Benchmark

The Linpack Benchmark was produced from the "LINPACK" package of linear algebra routines. It became the primary benchmark for scientific applications, particularly under Unix, from the mid 1980's, with a slant towards supercomputer performance. The original double precision C version, used here, operates on 100x100 matrices. Performance is governed by an inner loop in function daxpy() with a linked triad dy[i] = dy[i] + da * dx[i], and is measured in Millions of Floating Point Operations Per Second (MFLOPS).

Livermore Loops Benchmark

This original main benchmark for supercomputers was first introduced in 1970, initially comprising 14 kernels of numerical application, written in Fortran. This was increased to 24 kernels in the 1980s. Performance measurements are in terms of Millions of Floating Point Operations Per Second or MFLOPS. The kernels are executed three times with different double precision data array sizes.

Memory Speed BenchmarkMemSpeed benchmark measures data reading speeds in MegaBytes per second carrying out calculations on arrays of cache and RAM data, normally sized 2 x 4 KB to 2 x 4 MB. Calculations are as shown in the results headings. For the first two double precision tests, speed in Million Floating Point Operations Per Second (MFLOPS) can be calculated by dividing MB/second by 8 and 16. For single precision divide by 4 and 8. A disassembly showed that Millions of [Assembler] Instructions Per Second (MIPS), for the first two integer tests, can be calculated by multiplying MB/second by 0.78 and 0.59. For the three copy tests, MIPS are MB/second times 0.344 for double precision and 0.688 for the other two.

Bus Speed BenchmarkThis benchmark is designed to identify reading data in bursts over buses. The program starts by reading a word (4 bytes) with an address increment of 32 words (128 bytes) before reading another word. The increment is reduced by half on successive tests, until all data is read.