Upgrading your PC - How hard can it be?

                     By Richard Hewison

Reading James Judge's article in issue 41 (Obsolescence - It IS
Avoidable) brought back memories of my own recent experiences with
upgrading an old 386 33mhz into a 486 DX2 66Mhz. A friend has also
just upgraded his 486 DX2 66Mhz into a DX4 100 Mhz.

Adding extra memory to your PC can be a pain in the neck depending
on your Motherboard. We have two PCs, and they both have slots for
30 pin and the newer 72 pin SIMMs. Both Motherboards insist on
having the first four 30 pin SIMM slots populated if you are to
use 30 pin SIMMs at all. So, if you want 16 Meg of 30 pin SIMMs
then you must have 4 x 4Mb 30 pin boards and they must use those
first four slots. In addition to this restriction, you often find
that you have to be careful when mixing 30 pin and 72 pin SIMMs on
the same board. One of our PCs uses two 4Mb Double Sided 72 pin
SIMMs to make up the machine's 8Mb of memory. To add memory to
that system should be simple - just add in 30 pin SIMMs into the
four empty slots below. If only! Technical restrictions mean that
if the machine uses the 30 pin slots, only a single sided 72 pin
board can be used in the second 72 pin slot (still with me?).
What this means is that I have two choices if I want to upgrade to
16 Mb.  Either way we are forced to remove the 8Mb in the machine
and buy all new chips for the 16Mb (either 4 x 4Mb of 30 pin or 2
x 8 of 72 pin). Needless to say the manufacturers didn't mention
this piece of information when we bought the machine originally!
Another alternative are 'SIMM Savers' which are small boards that
allow you to plug in 30 pin SIMMS into a 72 pin slot.
Unfortunately, they can take up quite a lot of room when plugged
in and there might not be enough physical room inside the case to
fit one!

Sometimes you are forced into upgrading your Motherboard. As James
mentioned in his original article, the number of Motherboard types
is quite varied. VL bus Motherboards are becoming much harder to
buy now. Our old (1991) 386 Motherboard had four ISA (16 bit)
slots and two 8 bit slots. The early 486 Motherboards typically
had three or four VL slots and three or four ISA (16 bit) slots.
However, the introduction of PCI just over two years ago meant the
beginning of the end for the VL bus standard. We found this
puzzling, as we were expecting the old ISA slots to get the push
first! Our other 486 has all three (ISA, VL and PCI) but today
this kind of board is quite rare. New boards now only use ISA and
PCI slots, which might be a problem if most of your current cards
are VL! To add to the peripheral confusion, there are now 72 pin
EDO SIMMs that require EDO specific 72 pin slots. It might seem
obvious, but be sure the Motherboard you buy will take the type of
memory your machine currently uses, unless you fancy buying all
new memory. The other thing to consider is whether a new
Motherboard will fit inside your existing case. When building our
486 out of the ashes of our old 386, we had to buy a new case as
the old Motherboard was a different size to the newer 486
replacement.

You should also think about the possibility of upgrading your CPU.
Once again, whether or not your machine can do this is down to the
Motherboard you intend using with the new processor. The early 486
Motherboards can typically only take up to a 486 DX2 running at 66
Mhz. For this reason, Intel have unleashed the 'Overdrive'
Processors that (in theory) allow you to upgrade from a 486 DX2 to
a DX4 100Mhz or a Pentium. However, the latter is only possible if
your Motherboard can handle P24T technology. If not, then you
should stick with the DX4 100Mhz Overdrive upgrade instead. As
long as you have a ZIF socket (series 3,4 or 5) you can just lift
out your DX2 processor and plonk in the DX4 in its place. On the
other hand, if your 486 can take a 'real' DX4 processor then you
just need to go out and buy a DX4 CPU and fit that instead. In
terms of performance improvements, a DX4 100mhz should give your
old DX2 66Mhz a 50% increase, whilst a Pentium 83Mhz Overdrive
should give you up to 250%! (approximately the equivalent of a
P75). The voltage used by your Motherboard is also very important
when considering a processor upgrade. DX4s consume 3.3v so using
one on a 5v board could cause the CPU to burn out. The Intel
Overdrive upgrades can cater for this, so be sure to ask for the
correct version when buying (ask for one that allows a DX4
overdrive on a 5v Motherboard). Unfortunately, not all Motherboard
BIOS' are compatible with an upgraded CPU. If you have problems
with an Intel processor you can phone their customer helpline (UK
- 01793 431155) and they should be able to tell you if your BIOS
is okay. It's a very good idea to call them before you buy either
the Motherboard or the CPU upgrade, so you can check first. It
isn't easy to get an upgraded BIOS without changing the
Motherboard!

Upgrading hard disks can also be problematical. If you use DOS
6.22 then under normal conditions you can only use a hard disk up
to 528Mb in size.  With 1 GB disks become fairly standard, you
need to use special software to format them to the full 1 Gb
capacity and thus fool DOS (and Win 3.11). If you add another hard
disk, you have to ensure that it will work with your current model
(buying the same make usually works). Don't forget to set the
jumpers to master and slave settings, else the PC won't know which
drive to boot from.

When adding an additional hard disk to your system, you might
discover that your I/O Controller card can't accommodate two hard
disks from one IDE connector. Check out the cable which attaches
your hard disk to the card. If it doesn't have an extra connector
half way down (for a second drive) then you can be fairly sure
your card can't take more than one. Fortunately, Input/Output
Controller cards are also upgradable (if yours isn't built into
your Motherboard). You can now use the faster UART chips (16550)
for communicating through COM 1 and COM 2 and these allow for
improved baud rates etc. Some software now insists on using 16550
for modem or null-modem link options. You can also now get
enhanced parallel ports (bi-directional) on the I/O & Controller
cards. Once again, buying VL cards with all these features is
becoming a little more difficult than in the past, but they are
worth it and are quite cheap too. However, you might come across a
problem or two if you already use IDE devices other than Hard
Disks and you are buying an I/O card that has more IDE connectors
available than your previous one. All Motherboards have a limit to
the number of IDE devices they can have connected to them. I had
an IDE Sound Blaster 16 card with a CD-ROM drive connected to it.
When I installed my nice new EIDE I/O & Controller card (with two
IDE connectors allowing four IDE devices in total), my CD-ROM
drive failed to work anymore. After a bit of fiddling, the
solution became clear.  To use these two cards together, I had to
disable (via jumpers) the secondary IDE connector on the I/O &
Controller card. Fortunately, I don't foresee a time when I will
need the other connector, but you need to be aware of any
potential conflicts like this in case you already do use a couple
of IDE devices.

Of course, the situation today is out of control. Already, the P60
and P75 are being abandoned by manufacturers and the P90 is now
the entry level PC!  VL is all but extinct. 1 Gb Hard disks are
the norm and 30 pin SIMMs are harder to find and more expensive to
buy than 72 pin. 8Mb of memory is the absolute minimum (16 Mb
preferred) and you really need 2 Mb on your graphics card...or do
you? Computer technology today doesn't stand still for more than 5
minutes anyway. You will always be behind the times no matter what
specification machine you buy. I blame the U.S. Their machines are
cheaper and so they don't feel so bad ditching them every other
year for the latest model. After adding a little more memory and
upgrading the processor via an Overdrive chip, I'm opting out of
the upgrade business. In two years time the Pentium will have been
superseded all together, so I'm going to wait for the next new
generation before buying any more PC hardware. Anyway, I can't
afford it and there's tons of software out there that will run
quite happily on a 486!

To conclude, here is a typical list of upgrade prices I found by
trawling through a few PC magazines recently (early - mid 1996
prices):

ISA, PCI Motherboard (NOT Triton): œ79 + VAT (No CPU)
486 DX4 100Mhz: œ49 + VAT
486 DX4 100Mhz Overdrive: œ110 + VAT
Pentium 83Mhz Overdrive: œ189 + VAT
PCI 2Mb Graphics Card: œ129 + VAT
4 Mb 30 pin SIMM: œ89 + VAT
8Mb 72 pin SIMM: œ149 + VAT
1 Gb IDE Hard Disk: œ149 + VAT
EIDE I/O & Controller Card: œ14 + VAT
Mini Tower case (with PSU): œ29 + VAT
SIMM Saver: œ29 + VAT

Upgrading can therefore be reasonably cheap, or very expensive
depending on the hardware you own already. What might have been a
bargain computer 12 -18 months ago might now turn out to be a
machine which needs most (if not all) of its own vital organs
replaced to keep up with the latest software.














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