Contents of the VS.DOC file
Documentation for VgaSpeed VGA Graphics Benchmark Program
By: J. Rockford Cogar
119 Oklahoma Avenue
Oak Ridge, TN 37830
Use: VgaSpeed is FreeWare. This program may be used any way you wish,
as long as you do not charge any money for the program itself.
The program VgaSpeed is a VGA Graphics Benchmark Program. What VgaSpeed
measures is how fast a given computer system can generate VGA graphics. There
are several important hardware characteristics that determine how fast a
computer can do graphics operations:
1. CPU Speed
2. Expansion Bus Speed
3. Number of Video Wait States
4. Speed of Internal VGA Card Operations
An example of a fast graphics machine would include the following: a 33 mhz
80486 CPU, a 10 mhz bus speed, very few video wait states and a 'fast' VGA
Because graphics operations on VGA cards are mostly 8 bit I/O operations, 16
bit bus connectors on VGA cards do not appear to greatly improve the speed of
The results of VgaSpeed are given as relative to the graphics performance of
an IBM PS/2 Model 60 VGA system as a VS (VgaSpeed) number.
A VS of 2.00, would show that the current system has the ability to do VGA
graphics twice as fast as an IBM PS/2 Model 60 VGA. The fastest 80486 system
that has been measured gave a VS of about 2.70. Typical 80386SX VGA systems
yield VS numbers of about 1.40. It is around VS numbers equal to 1.40 that
Microsoft Windows 3.0 starts to look fairly good.
II. The Tests.
VgaSpeed is made up of four different graphics tests: Write Mode Zero Dot
Test, Write Mode Two Dot Test, Bit Map Move Test and Bit Map Text Test.
The graphics code in VgaSpeed was written in assembly language from
documentation in the IBM EGA and VGA Technical Reference Guides. Every effort
was made to make the code as fast as possible. After all, the goal is too
find out how fast a given system can do VGA graphics, not how fast the the
system can run a bunch of code through the CPU.
VgaSpeed was written using Borland Turbo Assembler 2.0 and Borland Turbo
By default, all tests are executed while the BIOS video mode was '16'. This
is the same as EGA 640 pixels horizontal by 350 pixels vertical 16 color
mode. This allows VgaSpeed to be run on EGA video systems.
When VgaSpeed is run in VGA 640 x 480, 16 color mode (by using the 'v'
command line switch) the VS number will be almost exactly the same as a test
of EGA 640 x 360, 16 color mode. The graphics testing takes about 40
seconds on a fast 80486 system to 140 seconds on an 8mhz AT system.
1. Write Mode Zero Dot Test.
This test draws 817,452 dots (pixels) on the graphics screen using
hardware write mode zero. Hardware write mode zero is the write mode used
by most graphics programs. It appears that Microsoft Windows 3.0 uses
write mode for all in all EGA and VGA type driver programs.
2. Write Mode Two Dot Test.
This test draws 1,634,904 dots (pixels) on the graphics screen using
hardware write mode two. In general, the process of writing a pixel to the
graphics screen in write mode two is twice as fast as one written using
write mode zero. Hardware write mode two is the mode used by most very
high performance graphics programs. For example, all of the EGA/VGA
graphics based data acquistion software from Tennelec/Nucleus Inc. (Oak
Ridge TN), use hardware write mode two. Some of the faster commercial CAD
packages also appear to use hardware write mode two.
3. Bit Map Move Test.
This test does 504 bitmap block moves. The size of the bitmap is 30,102
pixels (a 173 by 174 rectangle). The pattern leftover from the write mode
two dot test is copied from video RAM to system RAM, then from system RAM
to a different location in video RAM. This process is repeated 252 times.
The hardware write mode here is 'zero'. It is likely that most all
programs that use bit map moves to/from video RAM to/from system RAM use
hardware write mode zero to do so.
Because this operation involves memory block moves (using the: REP MOVSW
operation), the number of memory wait states of the source and target
memory can be a major factor in the speed of this test. In addition,
computers with expansion bus speeds greater than the standard 8 mhz, do
well on this test.
4. Bit Map Text Test.
This test shows how fast text can be displayed on a graphics mode screen.
The Bit Map Text Test writes a 39 character string in an 8 pixel tall font
to the graphics screen 2048 times. In addition, a 40 character string is
written to the screen in an 14 pixel tall font 2048 times. Both fonts are
8 pixels wide. All this means that 14,286,848 pixels get written on the
screen in this test! The hardware write mode used in this here is 'two'.
II. System Requirements.
1. A color VGA or EGA video system with at least 128KB of video RAM.
2. DOS version 2.0 or greater.
3. 64KB of free RAM.