            HOW TO UPGRADE YOUR 386 OR 486 PROCESSOR CHIP
                     Submitted by: Gloria Short


  One way to pull your increasingly old-fashioned computer back
  into the forefront of technology is to upgrade its central
  processing unit (CPU) by swapping out your existing 386 or slow
  486 chip for a hot new 486 screamer. (Pentium chip upgrades are
  still in the future.)

  Unfortunately, not all computers are candidates for a chip swap.
  Many popular mid-tier brand companies built their machines in a
  non-standard way, making upgrading impossible except perhaps with
  their own proprietary equipment. Examples include Leading Edge,
  Packard Bell, Hyundai, and Epson. Those who bought more generic
  clones will have an easier time upgrading their CPUs.

  WHO CAN UPGRADE? You can upgrade even an old 286 chip to a 486,
  but it won't help much because the bus and the rest of the
  computer's components will slow everything down too much. A full
  motherboard upgrade is often the better choice for a 286, because
  it replaces many of the bottle-necked components.

  With any computer, you'll want to consider the age of the
  computer before deciding to upgrade it. Older computers may be
  like my first car, a four-year-old Mercury that was in pretty
  good shape. After a year, things began to fail. First, I had to
  replace the starter solenoid. Then came radiator problems, a ring
  job, alternator replacement, and so forth. After a couple years,
  I'd replaced almost everything under the hood. When the starter
  solenoid went out again, I knew it was time to get rid of the
  car. If your computer is aging, replacing the CPU may not be cost
  effective if the other components are due to wear out soon.

  Any 386SX or 386 computer that's built to industry standards is a
  likely upgrade candidate. Finding out if it can be upgraded can
  be a ticklish task, though, because the upgrade vendor can't be
  expected to know the exact configuration of all of the thousands
  of clones built over the years. You'll need to consult with the
  upgrade vendor and perhaps the computer manufacturer to get all
  the information needed to determine if an upgrade will work. Some
  older units may require a BIOS upgrade along with the chip swap.

  If you have a 486SX or 486DX that runs at 16, 25, or 33 MHz,
  you're in luck. They're virtually all upgradable through Intel's
  OverDrive technology. Many have a separate socket built into the
  motherboard just for the purpose of inserting a clock-doubling
  486 chip. It replaces the original CPU by completely disabling it
  and taking over its functions. In computers without the extra
  socket, you simply replace the original CPU chip.

  WHAT'S THE BENEFIT? If you're wondering why someone with a 33 MHz
  486DX would want to upgrade his or her system, consider that
  putting in an OverDrive chip would increase the speed from 33 MHz
  to 66 MHz. That's twice as fast, isn't it?

  The answer to that question is yes--and no. Yes, some functions
  will be exactly twice as fast. No, some functions won't change at
  all. The exact amount of performance gain for any given task will
  vary, depending on which of your computer's resources are used to
  accomplish the task.

  Changing a 33 to an overdriven 66 doubles the speed of functions
  within the CPU, but the system continues to communicate with all
  the other components at the original 33-MHz speed. Thus
  CPU-intensive tasks such as calculation, record sorting, and word
  searches take place at twice the speed. But when the task
  involves getting data from the disk, rewriting the screen, or
  other non-CPU functions, there's little difference. Since almost
  all tasks involve both kinds of operations, the overall speed
  increase will be less than double, but still quite noticeable.

  Replacing a 486SX with a 486DX OverDrive chip adds a math
  coprocessor to the system. This speeds up floating-point math
  operations, which are calculation-intensive tasks such as the
  mathematical operations in spreadsheets and the vector graphics
  calculations in CAD programs.

  Converting a 386 computer to a 486 gives additional speed over
  the mere clock speed because the 486 thinks faster. In this
  rarified atmosphere, everything makes a speed difference. An
  Intel 486DX chip has an 8K internal cache, for instance. This
  cache buffers data that the CPU would normally obtain from the
  system's RAM memory. If the CPU can read and write data through
  the cache rather than the external RAM, it's faster. Yes, even
  the speed difference between the CPU and external RAM is
  significant. In a clock-doubled system, the internal cache
  operation becomes even more significant.

  A 486DX chip includes a built-in math coprocessor, but a 486SX
  doesn't. (Actually, it does, but it's masked off and doesn't
  function. Intel took a lot of heat for intentionally disabling
  part of the CPU chip, then selling it for less.
