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MAKING THE GRADE
STANDFIRST
So, you want to get into desktop video, maybe
you’ve already got a PC, but should you upgrade, or replace? Rick Maybury puts
his expansion cards on the table
COPY
Buy a vacuum cleaner, TV or VCR today, and
barring breakdowns, you can reasonably expect it still to be doing the job it
was designed to do in five to eight years time. Unfortunately the same cannot
be said of a new PC. The pace of processor development is such that it will be
virtually obsolete before it leaves the shop, and worth a fraction of what you
paid for it in a couple of years time. The good news is that it will probably
still be working just fine...
The trouble is, a state-of-the-art PC brought
five years ago for £1500, is incapable of running most of today’s high-powered
applications, and in desktop video terms, it is almost worthless. Or is it? In
fact 386 and 486 PCs still have a useful role to play, running simple camcorder
edit control and title generator software (with a VGA to video output device or
genlock), but realistically that’s about as far as you can go, without spending
some serious money on upgrade components, or a new machine.
In theory it’s possible to upgrade even the
earliest IBM compatible PCs to a high-performance multi-media specification,
though the only parts that would be left from the original are the case and the
keyboard. The decision to upgrade, as opposed to buying a new machine, is a
tough one, but the plain fact is, if you want to use the very latest desktop
video hardware and software, and stay ahead of the game for a year or so, then
you have little choice but to bite the bullet and buy a new PC, though you will
have the added advantage of a pre-installed operating system, bundled software,
extra hardware and a manufacturers guarantee.
If your present PC and aspirations are more
modest, then upgrading becomes a viable alternative, but where do you start?
Basically there are four key components in a PC, that determine power, speed
and capacity, and ultimately its suitability for desktop video. They are the
central processor (CPU), the main board or motherboard, the amount of random
access memory or RAM, and the size of the hard disc drive. Upgrading one or all
of them will make a difference, but you have to decide how far you and your
budget can go.
MORE MEMORY
The cheapest and simplest way of making a PC
run faster and more efficiently is to increase the size of its RAM, though there
are limits, and it can do nothing to improve actual processor power. Memory
prices have fallen dramatically in the past two years, and despite scare
stories about imminent price rises, it remains the single most cost-effective
upgrade for the vast majority of PCs.
Dynamic random access memory (DRAM) chips are
mounted on small printed circuit
boards, called SIMMs (serial in-line memory module) or DIMMs (dual in-line
memory module), with 30, 72 or 168 pins (though the latter is only used on the
very latest PCs). They’re located in ‘banks’ of sockets on the motherboard.
Adding new memory modules is actually quite easy, though if you haven’t had the
lid off your machine before, or you don’t fancy the idea of poking around
inside, you may want to have it fitted by an engineer.
However, before you do anything you must know
the type and configuration of memory your machine can use. This will normally
be contained in the operating instructions, or motherboard manual that should
have come with your PC. The first thing to determine is which kind of module
you can use. Most 386 motherboards only accept 30 pin SIMMs; 486 mainboards
often have both 30 and 72 pin sockets. Pentium-compatible boards generally have
72 and 168 pin sockets. Secondly the type of memory is important, there are two
main parameters: parity, and speed. It is possible to mix different types (i.e.
use parity memory upgrades with existing non-parity RAM, but not the other way
around), though it is generally safest to upgrade with the same sort that you already
have. Faster 486 and Pentium machines also have the option of using EDO
(extended data out) RAM, and it’s important to use the same type.
It is difficult to generalise about memory
configurations but it is usual for the upgrade to double the size of the PC’s
RAM. For example, if your machine has 4Mb of RAM, the next logical step would
be 8Mb; 8Mb increases to 16Mb, 16Mb to 32Mb, and so on. Companies selling RAM
modules will normally talk you through the selection procedure, so it is
helpful to have the make, model, type of PC and processor and if possible, the
name or type of motherboard to hand when ordering.
If all the available slots on the motherboard
are populated you may be able to part-exchange old modules for new ones, or use
an expander socket, which has slots to use your old boards, combining them into
one SIMM or DIMM.
Memory chips can be damaged or destroyed by
static discharge so they should be handled with care. Do not remove them from
their protective packaging until you have first discharged yourself by touching
the PC’s metal chassis. (The PC should always be disconnected from the mains
before you delve inside, unearthed metalwork will still dissipate a static charge).
If the sockets are obscured by cables move them gently out of the way, or
better still make a note of where they go, and remove them, so you can get at
the sockets. Memory boards usually fit only one way around, so observe the
position of notches in the connector strip. On most sockets the boards slide in
at an angle, and snap into position as they’re tipped towards the vertical.
Replace the leads, and the cover and switch
on. You may get a warning message from the BIOS at boot-up, but the machine
should automatically recognise the new memory and ask you to accept the updated
configuration. Check the memory test report, after boot up, to make sure the
RAM is properly installed, then sit back and watch it fly.
CHIP CHOP
CPU upgrades are the next most effective
performance upgrades, though it is really only worth doing on better-specified
486 and low-end Pentium models, and you may also need extra memory to get the
most out of it. How far and how fast you can go will depend on the design of
the motherboard but it is possible to achieve Pentium-class performance on a
486 for around £100, which is a good deal less than installing a Pentium motherboard
and processor. However although it will
enable you to run Windows 95 at something like a decent speed and many software
packages will run a lot faster, it will do little for the latest desktop video applications,
which depend on the full spec Pentium chip architecture and motherboard bus
systems.
The economics of a straightforward Pentium
upgrade are a little easier, and depending on the motherboard facilities, it is
possible to replace a Pentium chip with a faster model, up to and including the
most recent 200MHz MMX versions, which are eminently suitable for high-end DTV
applications..
The same general precautions apply in a CPU
swap as a memory upgrade, including disconnecting the mains supply, and
‘earthing’ yourself on the chassis, before you touch anything. Next, locate the
processor, or empty overdrive socket, in the case of some 486 boards. Most
processor upgrade kits come with CPU removal tools, to make the job easier.
Many motherboards have what’s known as ‘zero insertion force’ or ZIFF sockets,
these usually have little levers on the side, to release the chip. Once the old
CPU has been taken out the new one can be fitted, remembering to observe the
correct orientation. The new CPU can often be a good deal bulkier than the chip
it is replacing and may be fitted with a heatsink and on-chip fan, so make sure
there’s plenty of room around the processor, for cooling air to circulate, and
that the leads do not obstruct the fan. It may also be necessary to change jumper
settings on the main board, install additional software or make changes to the
PC’s BIOS, but these relatively simple procedures are normally clearly outlined
in the instructions.
BOARD TO TEARS
In many cases a CPU swap only delays the
inevitable and at best is only a stop-gap solution. It is usually far better to
change the motherboard as well, especially if the old one is more than a couple
of years old. Most mother board conform to the IBM AT standard and will fit
most cases, but do check before you buy,
especially if your machine is made by one of the big-names, who may use their
own proprietary main boards.
Motherboard swapping looks more difficult
than it is but if you approach it in a systematic manner, it needn’t take more
than an hour or so. It’s always a good idea to establish a fail-safe position
before you begin, so that if it all goes horribly wrong, you can at least get
back to where you were. Make a sketch of where all the boards and cables go, or
better still, take a colour photograph of your PCs innards. Make a note of where
the switch and display leads go, the connectors are usually marked. Remove all of the cables and expansion
boards, you should then be able to locate the one or two screws holding the
board into the case. Once they out you should be able to slide the board out.
If necessary unlatch any supporting pillars with a pair of long nosed pliers.
Replacement is a reversal of the removal
procedure, though you may need to re-position the supporting pillars, to align
with the holes on the new board. Once it is secure you can re-fit the power,
switch and display cables, memory modules, the old expansion cards, and any new
ones. If you’re moving up from a 486 to a Pentium you will probably want to
replace the old ISA graphics card with a faster PCI bus type. You probably won’t
need your old IDE drive card as most recent motherboards have the disc drive
electronics and connectors on board. The new board will have to detect and configure
itself to the disc drives, but this is normally carried out automatically by
the board’s BIOS system, when it is switched on for the first time.
SLIPPED DISCS
Whatever upgrade path you choose, one thing
is certain, sooner or later you will need a larger hard disc drive. Buy the
biggest, fastest drive you can afford; if you’re building a high-end system it
is worth spending some time on the various high-performance options -- see the in-depth
feature on hard discs in issue one of Computer Video.
Hard drive upgrades are generally quite
simple. The easiest method is to slave the new drive to the existing one, there
should be a label indicating appropriate jumper settings on both drives. This
is also quite useful in DTV applications, where the new drive can be dedicated
to storing large video files. Slaving the new drive is also an easy way of
moving lots of files over to the new drive, prior to retiring the old one.
Standard HD drives are normally held in place
by four screws, and connected by two or three cables, one for power, one for
data, and possibly one for the HD activity light on the front panel. Once the
swap has been completed the BIOS will need to detect and configure the new
drive, install the operating system and application and you’re in business.
BOX COPY 1
TEN TOP TIPS
* Buying new is generally preferable to upgrading,
you probably won’t save a great deal of money, moreover a new machine will come
with bundled software, and a warranty!
* Often, by upgrading you will expose
shortcomings in another area, so don’t expect simply to replace just one component
* If you don’t feel competent to upgrade your
machine don’t take risks, pay to have the modifications done by an engineer
* Whatever the upgrade observe sensible
precautions, like disconnecting the machine from the mains before you start
work, and discharging yourself, before you touch any static-sensitive
components
* When adding extra RAM make sure it is the
correct type, parity and speed, consult your manual, before you buy
* If you run out of spare RAM sockets you can
still use your old modules by using expander cards
* A 486 to ‘Pentium’ CPU upgrade is really
only a stop-gap measure, it is far better to buy the processor and motherboard
together, which should also ensure they are configured correctly
* The commonest cause of apparent hard disc
failure is incorrect setting of jumpers
* Make sure your case will accept a standard
AT type motherboard, some PC manufacturers make their own non-standard boards,
that cannot be easily updated or replaced
* If you’re on a very tight budget you may be
able to part-fund the upgrade by selling retired components in magazines like
Micro Mart
---end---
Ó R. Maybury 1997 1905
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