206 lines
8.5 KiB
Plaintext
206 lines
8.5 KiB
Plaintext
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# ## # # ## # #####
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###### ### ## ### #####
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------------------------------------------------------------------
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| Technical News Association |
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| #1 |
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| The 486 Chips and How The Stack Up |
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| Skyewalker |
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------------------------------------------------------------------
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Just take one look in any of the latest issues of good
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computer magazines, and they all say the same thing, "The 386
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is dead" For the most part they are right, seeing as you can
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buy 486 computer systems for under $1000 now, it hardly seems
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practical to go for a 386 system anymore. Looking through the
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same computer magazines, you will also see many different
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types of chips, that all have the same three digits, 486.
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This article will make an attempt to make some sense out of
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the many different types of 486 chips, it in no means is
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meant to be a technical reference.
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The first thing to notice about the new line of chips is
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what comes after the numbers 486! Such letters as SX, DX,
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DX2, SLC, and DLC to name a few. The list below show many of
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the popular chips in the 486 line.
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Intel Cyrix IBM
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486SX-16 486SLC-20 486SLC2-20
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486SX-20 486SLC-25
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486SX-25 486DLC-25
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486SX-33 486DLC-33
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486DX-33 486DLC-40
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486DX-50
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486DX2-50
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486DX2-66
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Overdrive
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As you can see, there are many chips to choose from, and
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the above list is not complete. Each has it's own different
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features, the following is a description of each type of chip
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in the 486 line in order of speed and company.
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Intel
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486SX - This is the bottom of the line, of Intel chips,
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coming in 16, 20, 25, and 33 mhz version's, it caused quite a
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bit of confusion among people when first released. The term
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SX has changed a lot since it's inception in the 386 line,
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while the 386SX had a 32bit architecture, it had a 16bit bus,
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thus making it cheaper for low end computer models. This is
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not so in the 486SX, it has a full 32bit architecture, and an
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optimized instruction set, complete with 8k of internal
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cache. What makes it different from the DX is that it's math
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co-processor has either been permanently disabled, or is
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simply not present at all.
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486DX - This chip is what's known as a "full" 486 chip, it
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has a full 32bit architecture, 8k of internal cache, and a
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math co-processor built in, making faster overall than the SX
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model. This chip now comes in 33, and 50 mhz versions.
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486DX2 - This type of chip has a lot of misconceptions
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surrounding it. The DX2 uses a phrase called "clock doubler
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technology" which, as it states, doubles the internal clock
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speed, the chip runs just like a 486DX-33 (486DX-66 mhz
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version) except for it's internal 66mhz processing, but of
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course is faster overall than a 486DX-33 because of it's raw
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calculation speed, and boosting such things as DOS video
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operations, the chip is available in 50 and 66 mhz versions.
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Overdrive - This is a chip in the 486 line that has seen much
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attention, and quite a lot of adds on the television. This is
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Intel's answer to the never-ending need to upgrade your
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computer. Take a look on all but the first ever 486
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motherboards, and you'll notice an empty socket. This socket
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is sometimes known as a "vacancy" socket. It's meant to
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accept an Intel Overdrive. What an Overdrive does is plugs
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into a 486SX Motherboard, and turns a 486SX-25 into a 486DX2-
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50 (slightly slower than a DX2-50) and is now also available
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for 486DX's to turn a 486DX-25 into a 486DX2-50, and a 486DX-
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33 into a 486DX2-66. It uses "clock doubler technology" (as
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explained above) and fits into a 487SX co-processor socket.
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Cyrix
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486SLC - This chip still has many people wondering if it
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should be called a 486, or just a faster 386. In essence it
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is simply a pin compatible replacement for a 386SX. And like
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the 386SX it has only a 16bit bus, while keeping the internal
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32bit architecture. The chip also has only 1k of internal
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cache, and no math co-processor. The lack of an internal math
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co-processor is in fact rumored to be a way of getting
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around any patents by Intel on the 486 line. Instead Cyrix
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bundles a Cx87DLC math co-processor with many of it's SLC's,
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which improves performance. The SLC comes in 20 and 25 mhz
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versions.
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486DLC - This chip is made to compete with the Intel 486DX
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line of chips. It still comes with only 1k of internal cache,
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but like all DX's has a full 32bit architecture, that is
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capable of addressing up to 4 gigabytes of RAM. The 1k of
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internal cache may seem to be not enough, but as Cyrix points
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out, most 486 motherboards come with at least 64k of onboard
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cache, making the need for on chip cache neglagable. This
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chip comes in 25, 33 and 40 mhz versions.
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IBM
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486SLC2 - This chip is meant for the portable computer
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market. It handles most things an Intel 486SX-25 would do.
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The IBM SLC2 has the largest internal cache of any chip in
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the 486 line so far, at 16k. The lack of an internal math co-
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processor and only a 16bit bus (like a 386SX) makes it cheap,
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and small, thus perfect for notebook type computers. The chip
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also has "clock doubler technology" running internally at
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40 mhz, while running at 20 mhz externally.
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The above list was an example of most chips in the 486
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line. But because new chips are coming out all the time, many
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more will probably be available as you are reading this.
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What To Buy
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Now that you've seen the mess of chips available, it may
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be slightly confusing as to which chip would suit your needs,
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the following list may help you out in your decision.
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Type Of Computing You Do Chip Recommended
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General Purpose DOS Based 486DLC-25
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486SX-25
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486SLC
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DOS Based Graphics Or 486DLC-25
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Spreadsheet Work 486DLC-33
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486DX2-50
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Windows Environment For 486DLC-33
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Generic Applications 486DLC-40
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486DX-33
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Windows Environment For 486DLC-40
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Desktop Publishing 486DX-33
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486DX2-66
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Windows Environment For Intense 486DX-50
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Graphics, or CAD/CAM 486DX2-66
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OS/2 Or Unix In A Stand Alone 486DLC-40
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Configuration (High End) 486DX-33
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486DX2-66
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OS/2 Or Unix Very High End Applications 486DX-50
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486DX2-66
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The 486 chip you choose will defiantly depend on the
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types of applications you choose to work with, and what you
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want to get out of your computer. I hope this file has helped
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in some way for you to make a buying decision, or just
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understand more about all the different 486's out there.
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The information presented in this text file was meant to
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give a basic overview on the new 486 line of CPU's from
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different companies. It was in no way intended to have any
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"special" inside information, or technical talk, just a
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strait forward explanation of CPU's. And none of the
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information within can be guaranteed accurate at all.
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Skyewalker
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Skyline BBS
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908-363-3832
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Credits:
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Computer Shopper Dec 1992
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The Internet - hardware.pc (Eric S. Raymond)
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