You can see the table below of the results. Note that they are platform specific, i.e., changing the compiler or operation system or memory ammount or porting to another hardware may lead to other results (the index).
pibench.zip (68462 bytes) 16-bit i8086 (version, the source code works OK under OSF also).
pi_ben32.zip (88574 bytes) the same code compiled for i80386--Pentium (Win32 platforms only). Note that the code is not optimized for Pentium-Pro and compiled with emulator option, so the results of comparison Pentium and Pentium-Pro may surprize you (see table below).
pi_bench32.zip (220614 bytes) analog compiled with GNU FORTRAN (G77) for Win32 platform; as a GNU-compliant software it can be compiled on almost any platform.
My friend A.Dontsov has tested Pentium-166 and Pentium-Pro-200 and Pentium-II. The first two test were carried out in the same environment and the indexes were about 900 and 800 respectively (Win32 version, see below) and the difference was much more surprising with 16-bit version.
Celeron-300 overclocked to 450 MHz is about twice faster than an old DEC Alpha station. Overclocking is done by changing the bus speed to 100 MHz (PC-100 or similar DIMMs used). Celeron ignores switches on the motherboard and always multiplies the bus frequency by 4.5. Pentium-II of similar frequency is to show better results because of its cache (Celeron has none). The results may differ slightly if the task's "bottle-necks" fit the cache size.
Comparison results does not mean that this or that platform is "faster" or "slower". Of course, Pentium-Pro offered better average performance (as well as of particular applications) than Pentium or Pentium-MMX, but if you do scientific calculations then you can save your money :-).
Platforms are generally incomparable: different hardware architectures, sets and efficiencies of loaded processes, various number of users, memory speed, etc. Of course, one must have enough memory not to force swapping :-). The users, however, is not interested in these details. They need to know how fast their tasks are solved. The PC environments mainly differ in disk speed (particularly if SCSI is used), memory and processor speed. Disk performance means almost nothing to the benchmark, memory and processor speed may be roughly measured in Megahertz and additionally characterized by with the processor type. Roughly: Most PCs with processors of similar classes have memory of almost the same speed. So, to choose a computing environment you must make sure to have sufficient memory and an appropriate processor.
| Platform | OS | Compiler | Digits | Approximate index |
| DEC 3000-600S AXP (alpha) | OSF/1 (UNIX) | f77 | 64000 | 1100 |
| PC KT Intel 80386SX/80386 33 MHz | MS DOS 6.2 | MS-FORTRAN 5.0 | 8000 | 16 |
| PC WYSE 80286/80287 12 MHz | MS DOS 5.0 | MS-FORTRAN 5.0 | 4000 | 4.7 |
| PC SIS 486/256K/16M/AMD5x86 133 MHz | DOS 6.2 | MS-FORTRAN 5.0 | 4000 | 204 |
| PC SIS 486/256K/16M/AMD5x86 133 MHz | Windows-95 | MS-FORTRAN 5.0 | 4000 | 210 |
| PC SIS 486/256K/16M/AMD5x86 133 MHz | Windows-95 | MS-FORTRAN Power Station 4 | 8000 | 287 |
| PC SIS 486/256K/32M/AMD5x86 133 MHz | Windows-95 | GNU G77 0.5.20 | 4000 | 376 |
| PC Pentium-MMX 166 MHz | Windows-NT4 | MS-FORTRAN Power Station 4 | 16000 | 900 |
| PC Pentium-Pro 200 MHz | Windows-NT4 | MS-FORTRAN Power Station 4 | 16000 | 800 |
| PC Pentium-II 300 MHz | Windows-NT4 | MS-FORTRAN Power Station 4 | 16000 | 1040 |
| PC Celeron-300 at 450 MHz | Windows-98 | MS-FORTRAN Power Station 4 | 8000 | 1648 |
| PC Celeron-300 at 450 MHz | Windows-98 | both GNU G77 0.5.20 and EGCS 1.1 CygWin Beta-19 G77 0.5.24 |
8000 | 2259 |