PowerPC vs Intel - Processor
Performance Comparisons -BYTEmark
Below you will find various processor comparisons for PowerPC
and Intel based chips. Testing was done using BYTEmark
Byte Magazine's standard for measuring raw processor performance
and appeared in Byte Magazine.
Below you will find the scores for the individual test that
make up the BYTEmark testing suite expressed as the percentage
of performance when compared to the G3/300 which receives
a score of 100%. For information on these scores please visit
the BYTE Magazine web
site.
The BYTEmark benchmark test suite is used to determine how
the processor, its caches and coprocessors influence overall
system performance. Its measurements can indicate problems
with the processor subsystem and (since the processor is a
major influence on overall system performance) give us an
idea of how well a given system will perform.
The BYTEmark test suite is especially valuable since
it lets us directly compare computers with different processors
and operating systems. The code used in BYTEmark tests simulates
some of the real-world operations used by popular office and
technical applications.
What do the different test scores in the suite mean?
There are 10 tests in the BYTEmark test suite. Each uses
a well-known algorithm to analyze the full spectrum of processor
performance in the same way real-world applications do. Some
tests concentrate on integer performance; others test floating
point capabilities. You can read more about the individual
tests and the operations they measure in the BYTEmark documentation.
It's available at http://www.byte.com/bmark/bdoc.htm.
Because processors don't always perform the same tasks in
the same way, and thus may sometimes give unexpected results
on individual tests within a benchmark suite, BYTEmark performs
statistical checks to confirm the validity of results.
What is the advantage of benchmark tests test suite?
PC test centers generally measure performance in two ways:
by performing controlled tasks with commercially-available
applications, and with custom-built programs designed to test
a particular facet of the computer system. Application-based
benchmarks perform tasks inside commercially available programs.
They're extremely useful for determining relative performance
within a given platform, and less useful for ranking performance
among machines that use different processor architectures.
The BYTEmark suite forces a system to perform carefully chosen
operations natively and in isolation, that is, without assistance
from an advanced operating system or other system resources
such as a fast hard drive or enhanced video subsystem. Application
benchmarks may show that a computer system is fast or slow,
but the BYTEmark tests can help determine if the change in
performance is due to extra memory or a faster processor,
for example. In certain cases they can also be used to demonstrate
obscure features (and sometimes flaws) in compilers or in
microprocessor architectures.
Remember, however, that a computer's overall system performance
is a composite of many factors : the processor, the speed
at which it and any L2 cache is clocked, the speed of its
physical memory, the speed of its hard drive, the speed of
its video subsystem and many other features. Vendors make
trade-offs when assembling computer systems in order to achieve
desired price points for new machines; these can cause two
machines using the same microprocessor to report very different
results.
Why do the Bitfield test results vary so much between the
two processors?
If you'll examine the chart carefully you'll notice that
one test, Bitfield, returns very high scores for the G3 when
compared to the Pentium II. The reason? The PowerPC compilers
used to build these applications can generate code that's
significantly different from that of x86 (i.e., Pentium) compilers.
What's the difference between these compilers?
A lot of it has to do with how the compilers generate code
for this test. Compilers generate code based on their knowledge
of the target processor's architecture. They use this information
to produce machine code that implements the algorithm most
efficiently.
Do compiler optimizations impact results?
Yes, because they take advantage of the processor architecture.
This is exactly what a software developer wants; it helps
speed the performance of the application he's creating.
Copyright 1996-2007 by Cider Press Publishing LLC all rights reserved.
MacSpeedZone is not authorized, sponsored, or otherwise approved by Apple
Computer. Apple, the Apple logo, Macintosh, iPod, iBook, iMac, eMac, and
PowerBook are registered trademarks of Apple Computer, Inc. Additional
company
and product names may be trademarks or registered trademarks and are hereby
acknowledged.
