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S) 4.0 Upgrading Processor/Coprocessor/Disks/Video/CDROM
Q) 4.1 I don't have
the money for a new computer or motherboard, what can I do?
[PC Magazine 11-08-94, alkemyst@shadow.net)
Kingston Technology makes upgrades to raise the level of all chips (i.e.
286 to 386, 386 to 486, 486 to 586). Some are CPU replacements, others
are daughterboard cards, and the granddaddy is the MCMaster. The
CPU replacements offer very little performance gain if your system is strapped
with slow peripherals and memory, but can get you running 386 or 486 software.
The
daughterboard 486/NOW! replaces both the CPU and math coprocessor,
but performance-wise it is a disappointment. The MCMaster is MCA
architecture in action. Using busmastering it allows the card to
take over CPU functions and make the computer run a lot faster using its
own 128k L2 cache and up to 32MB of memory. This card shows promise
and in most cases performs better than the daughterboards and CPU plug-ins,
however it lags slightly in DOS video
performance and video in general as it must 'cross' the bus on to the
motherboard. Still the MCMaster is probably the fastest in this list
and the only upgrade that can add L2 cache to computers without the option.
[Formats: 486/NOW!: models 70/80 to 33PD3 or 33PS3 (don't know
what the PD3 or PS3 maybe D=DX and S=SX.); MCMaster: for models 55,
56, 57, 65,
70, and 80: to 33 MHz or 50 MHz...note only 50 MHz with 8 MB+ boosted
performance
and so it did significantly. The price for this level is $1000-1400.][NDP:
built in to the 486 chip.]
Intel has a SnapIn 386 module for PS/2 models 50, 50Z and 60. It features
a 20 MHz 80386SX, 16K cache and it can utilize an existing 80287 math coprocessor.
I have one in a model 60 and have had no problems with it.
IBM offers for the 386 PS/2 Model 70 and 80 with 16 or 20 MHz processors
a Power Platform upgrade with a 486DX33 on it. See above IBM PARTS
LIST for features and part numbers. These are expensive ($500-700)
and are no longer made, but can still be obtained esp. from the Boulder
Parts Surplus Plant 800-388-7080.
IBM re-released the Blue Lightning chip for PS/2's again. This
time it is for the 25 MHz machines also. It offers 16K internal cache,
enhanced 386/486 instruction set, and 33/66 MHz performance (though the
33 will be replaced with whatever your system runs at). Also you
can add a math coprocessor. The L1 cache design is supposed to be
what sets this chip off from the rest (Hypertec). I talked to a IBM
tech who actually had the Cyrix DRx2-50 and was asked to help test out
this new chip. He stated he saw the same performance jump from going
to a Cx486DRx2-50 from his 386DX25 as going to the BL2 from the Cyrix.
I would call that an upgrade worth considering, esp. at the mere $345 IBM
is asking. IBMPN#13H6698 $345.
IBM also has a SLC2-66 chip out for 55SX offering up to 10x the performance.
Features 16K L1 cache, enhanced instruction set, and allows existing 387SX
usage providing it is a 33 MHz chip. IBMPN#13H6694 $259.
Cyrix offers very good options for the 386 to 486 conversion if you
are on a tight budget. Their DRx2 line offers clock doubled performance
at a low price. The chips perform very well and just require removal
of the 386 and popping in the new chip. Pricewise they can't be beat
and though not offering the performance of their $500+ cousins they come
close enough for most people at half the cost or more (This is due to their
tiny 1k L.1 caches). [Formats: 386 to 486 only: DX 16 MHz to
16/32 MHZ, DX 20 MHz to 20/40 MHz, 25 MHz to 25/50 MHz, DX 33 MHz to 33/66 MHz,
none for 40 MHz yet. DX 16 MHz and 20 MHz systems can use the 25 MHz chip
if available. Some versions for SX models.][NDP: 387,
Cyrix 83D87 rec.]
Evergreen's Rev to DX4 and 486 chips are more expensive and generally
faster than most others at a lower prices. One problem is compatibility,
many computers can not run at the clock tripled and quadrupled rates and
must fall back to clock doubled rate negating the extra cost of the upgrade.
Another note is the processor board cards will not work with all systems
due to space constraints, it is best to measure and make sure you got at
least 1" or more room above the processor and can afford to give up peripheral
card space if it is in the way. A processor card may be worth it
if it works due to the fact of a larger L1 cache and the usage of an IBM
Blue Lightning CPU in some formats. [Formats: 386 to 486: DX 16/20 MHz
to TI 486SXL2 or Blue Lightning 16/48 or 20/60, DX 25 MHz to TI 486SXL2 or
Blue Lightning 25/75,
DX 33 MHz to Blue Lightning 33/66 or 33/99; 486 to 486: SX/DX 25 MHz
to 25/75 MHz,
SX/DX 33 MHz to 33/99 MHz, SX/DX 50 MHz to 50/100 MHz. Note the DX4
only clock
triples or doubles not quadruples like a DX4 seems it should.][NDP:
various.]
H.Co is offering many chips now from 286 to 486 all the way to a 386
to DX4/100. I am interested to see how these perform as I have no
info other than formats available. [Formats: 286 to 486:
6-16 MHz to IBM 50 MHz; 386 to 486: SX/DX 16/20 MHz to TI 40 MHz, DX 25 MHz
to TI 50 MHz, DX 25 MHz to IBM 50 MHz, SX/DX 33 MHz to IBM 66 MHz, SX 16 MHz to
IBM 48 MHz, SX 20 MHz to IBM 60 MHz, DX 16/20 MHz to IBM 60 MHz, DX 25 MHz to
IBM 75 MHz, DX 33 to IBM 99 MHz; 486 to 486: 25 MHz to 75 MHz, 33 MHz to 100
MHz, 40 MHz to 100 MHz.][NDP: ?]
A small company called MicroModules System also offers CPU upgrades.
They are at 10500-A Ridgeview Court, Cupertino, CA 95014-0736.
408-864-7437. Then there are AOX Inc.'s MicroMASTER busmaster boards. From
386-20 to 486/33 with up to 8MB of RAM on board. This is what the
Kingston is now. Kingston bought the rights to manufacture the MicroMaster.
The early 286 to 386 versions can utilize 132PGA chips and usually 486DLC
and DRx2 chips
will work, but these are no longer made and must be found used or in
surplus warehouses. [Formats: 286 to 386: to 20 MHz, 25 MHz,
33 MHz][NDP: 387.]
In summary the MCMaster fully configured, i.e. 486/50 with 8 to 16MB
of RAM offered the best performance, followed closely by Evergreen's DX4,
Cyrix and finally Kingston. H.Co, IBM, Intel, and AOX were not tested.
Also note that adding 8MB of RAM will usually add as much performance
as the CPU upgrades do and add a lot more performance if combined with
the CPU upgrade. The addition of RAM, a Video card, faster hard drive,
and a new CPU will make the most improvement and if done over a period
of time makes sense, however if these are going to be bought 'lump sum'
it is probably better to buy a 486 clone if you are looking for speed.
If reliability is a big factor and speed not as important as being able
to run the new 386+ software then with PS/2's usually there are no problems
as there are with most clones.
Update as of 10/28/98, there are no processor cards (AOX MicroMaster
or MCMaster) available for the PS/2's anymore. Evergreen and Kingston
are still selling their processor upgrades and prices have fallen dramatically.
For the 486/33 systems you can get the AMD 586/133 (equivalent to a Pentium
75) for about $70 from CompUSA, Fry's, or Circuit City (list is about $129
for Evergreen's and $99 for Kingston).
Q) 4.2 What are the
Benchmarks for these Processor Upgrades?
Benchmarks are meaningless to give as it would not be the same machine
nor the same variables but below are some 'averages'. Benchmarks
are only good to compare the same settings to the same settings so if you
have a machine listed and have different marks don't post to USENET asking
why, as it is simply because you have a different configuration.
The basic outline discussed above gives you the breakdown in percent a
CPU upgrade is worth 36-134%, a daugtherboard is worth 137-681%(681% percent
seems high and was not supported by PC Magazine's data. The 137% seems
more real world as these are very close to direct CPU replacements for
the most part), and an MCA processor card 263% which offered the largest
increase, but at a very high
cost.
Also note that a 486 is just an enhanced 386 with L1 cache. This
L1 cache is responsible for up to a 500% performance increase. L2
caches can offer at most a 50% performance increase. Try disabling
all caching on a 33 MHz 486 and compare the marks to a 33 MHz 386 you will
be surprised how close they are.
Winstones are the most quoted benchmark today, so a table of average
Winstones was computed. Keep in mind that this benchmark is a benchmark
which rates the execution of certain popular sequences, scripts, in about
ten or so of the most popular window programs. With this in mind
this should give a *very* real world figure. Also keep in mind that
when the processor upgrades were done, the systems below remained stock
which is very crippling especially with
a 486 trying to pull files from a 20 ms access hard drive.
The processor quoted benchmarks came from a database of at least 50
different platforms each for the 25, 33, 2/50, 2/66 with the 33 and 66
MHz numbers being taken as an average of no less than 50 machines for each.
This should give a good average number as there was no price range or brand
criteria only what was available to the home user (i.e. no FCC class A
or non-FCC tested dynamos).
The 50 MHz numbers were for 5 tested machines. The AM40, CxS40,
and SLC2 numbers are for two or less machines each and may be bad examples
of the capability of the chips being either superior or inferior to average
numbers. The Pentium numbers came from an average by PC Magazine and should
be a good average figure.
Processor
Winstone Value
--------------------------------------------------
386/25 MHz Winstone base w/4MB 10.20
386/25 MHz Winstone base w/8MB 13.60
486/25 MHz
26.32
CxS40
29.95*
486/33 MHz
34.32
SLC2/50
36.70*
SLC2/66
37.80*
AMD40
40.30*
486DX2/50 MHz
43.50
486/50 MHz
47.94
486DX2/66 MHz
50.68
Pentium
73.30
CX486DRx2/50
14.20 --
Rev to 486 2/50
15.40 \
Rev to 486 3/75
18.00
486/Now!
11.20 /
MCMaster 50PD/8
15.00 --
Keep in mind these could vary a lotdepending what system the upgrade
is going into (i.e. MCMaster was only tested on a 386SX16 machine and the
rest a Compaq 386DX/25e with only 4MB and with 8MB the Rev to 486 2/50
did 23 Winstones and the 486/33 did 36. So with more memory and better
peripherals the upgrades should give truer 486 performance despite PC Magazines
slams against them in general.
Q) 4.3 Which Math Co-Processor
should I use?
For 286 systems a 287, 386 systems a 387 and for processor upgrades
usually the same unless they perform NDP functions on chip. It may
be wise to purchase an enhanced NDP, such as the 83D87 from Cyrix which
is much faster (5-15% in applications, up to 20% on certain benchmarks)
than the Intel part.
Q) 4.4 Replacing a
slow stock Hard Drive with a faster and larger capacity version
PS/2's are notorious for slow, low capacity hard drives. The Model
50's 20MB drive has 80 ms access! The easiest way to go is to add
a SCSI or ESDI card. SCSI in general offers better performance, the
ability to add up to 7 peripherals and easy to find drives. ESDI
offers more UNIX compatibility (though with new drivers this will change)
and was stock on some PS/2's, most now use SCSI. If you have SCSI
or ESDI already you can add at least one more drive no problem. It
is a bad idea in general to try and replace the MFM type ST-506 drives
on early PS/2s as buying a SCSI card and new hard drive is a cheaper, faster
and more reliable solution.
Keep in mind that if you add a SCSI drive and controller make sure the
controller has boot ability in the BIOS or else you will have to boot off
of the original PS/2 drive.
Q) 4.5 How can I add
a second floppy drive and what type will work with my PS/2?
Kits for mounting these drives can be obtained from PS Solutions 214-783-6997.
They sell high quality, complete kits for almost every possible internal
drive mounting option.
3.5" internal for:
25/30, 50Z/70, 50(front bay 50Z/70)
60/65/80
(via a 5.25" internal mount and allow for two half-high 3.5"/5.25"
mounts)
3.5" 'H'-skid type for:
35/40/56/57/76/77(via the 5.25" int. option)
5.25" internal for:
35/40/56/57/76/77(all with 3.5" mount options
available)
60/65/80
(vertical mount, also with dual half-high 3.5"/5.25"options)
90
(for removable media in the 5.25" bay w/ 3.5"HD opt.)
85/95
(for removable media and rails for fixed media)
For systems with 'slide-it-right-in' options the necessary bezels can
be obtained from DakTech 800-325-3238 very cheaply for a high quality product.
(Also for bezels with missing clear plastic 'windows' which make it hard
to see the drive lights.)
First, we will discuss the 3.5" addition as it is a more common event.
The first thing you need to do is to determine the MB capacity of what
you want to add. There is 720K/1.44MB/2.88MB and they can all read/write
at their level or lower (i.e. a 2.88MB can read/write 1.44MB and 720K).
Not all systems can use all 3.5" drives. [I would like to include
a list of which systems CAN'T use the 1.44MB drives and which systems CAN
use the 2.88MB
drive]. After determining what you need/want to add you can start
the installation.
*ADDING A 720K DRIVE:
*INTERNAL OPTION:
*EXTERNAL OPTION:
ADDING A 1.44MB DRIVE:
INTERNAL OPTION:
There are two types of 1.44MB drives and though they do the same thing
they are not interchangeable on the internal level. One has the disk
light above the media slot and the other has it below the media slot (there
are other ways to tell but this is the easiest method). Once
you determine this it is simply a matter of either popping off the faceplate
bezel blank sliding in the disk
drive until it 'clicks' and popping on the new bezel. Sometimes
the external case needs to be opened like a model 50 for example, but then
the procedure is the same.
*EXTERNAL OPTION:
*ADDING A 2.88MB DRIVE:
*INTERNAL OPTIONS:
*EXTERNAL OPTIONS:
Now we will discuss the addition of a 1.2MB 5.25" drive.
These can be both adding internally or externally. External is
the common way as most PS/2s do not provide a 5.25" floppy bay and those
that do usually require a vertical mounting arrangement.
*The models supporting a direct 5.25" mount internally are:
All other's need to either buy the kits listed above or need to use
an external mounting option.
*INTERNAL MOUNTING:
*The internal 5.25" drive is installed by sliding it into the bay
[someone please contact me with the directions for the direct installs
..do they click into place like the 3.5" drives or do they require
screws/or combination.]
The kit-type installations are completed by following the manufacturers
guidelines for the kit then going to the drive hookup section below.
*Hooking up the drive to the drive card:
EXTERNAL MOUNTING:
Find a place on you desk or area where the likelihood of the drive being
knocked down is low. Then set the drive down and detach the cable
if possible from the drive to prevent it being dragged around in the installation
procedures.
Now you are ready to set it up:
IBM:
Open the case of the computer, find an empty MCA slot. Plug in the
floppy controller card and run the cable to it. Now close up the
computer and plug in the 5.25" external drive and you should be all set.
Cristie drive (available only in the UK?):
The drive connects to the B-3.5" floppy connector. The cable then goes
inside the computer, through the slot in the back and finally to the drive.
It doesn't actually use a slot, but looks neater than having a cable run
out the front B: drive bay to the 5.25" drive.
Radio Shack/Tandy's 5.25":
This drive will give you 360 and 1.2mb formats via the parallel port,
and allows you to plug your printer in too -- so you lose neither a drive
bay, an expansion slot, or much money. The drive can be temperamental,
usually requiring a print job before the drive is acknowledged (maybe initialization
of the parallel port is what is required). The print job can be empty also.
This drive is an ideal solution which lets you keep your tape backup and
expansion cards in place, even if requiring an extra step to use the drive.
Sysgen unit:
Its not a very awkward installation. Just pop off the cover.
Unplug the floppy connector. Snap a small board in on supplied
post, and re-install the floppy connector and route the other out the box
to the external unit. It works as drive B in 1.2 meg mode. The IBM's
I saw mapped above the last hard drive, so that floppy came in as D or
E. Works fine with SCO Xenix too.
[I have been informed that the IBM drives also require the usage of
one of the 3.5" floppy bays for a second drive card, is this the case for
all 5 1/4" drives?]
Q) 4.5a What is the
Third floppy connector for?
That is for a floppy controller based Tape Drive (The ITBU comes to
mind). If you want to be retro, go for it, but any decent SCSI based tape
will clean the floor with a floppy controller tape.
I did run three floppy drives in a 90 once. W95 did not like it (MS-DOS
mode) but I was able to access all three floppy drives.
Q) 4.5b Will the *
floppy drives damage my floppy controller?
They are Mitsubishi MF356F-899MF 2.88MB floppy drives. They have the
"*" on the top of the blue eject button. Do NOT use * floppy drives in
a 9585 (all models), Lacuna based 76 / 77 systems, and in 95A (dual serial
/ parallel ports) planars. At this time, Peter Wendt opines
that the extra wires used by the security features on the listed systems
are not properly handled.
At present, I am confused. I pulled * floppy drives out of Bermudas
with a 44 pin floppy controller header. There does not seem to be a specific
floppy controller related to the problem, as the Bermudas had 82077AA,
82077SL, or NS PC8477AV with * floppy drives attached.
Q) 4.6 Is there a SVGA
option for my PS/2?
There's XGA and XGA/2 from IBM and the Reply Video Adapter from Reply
Technologies. Both of these have 1MB of unexpandable VRAM and can display
256 colors at 1024x768 non-interlaced and go to 1280x1024x16. The
IBM card uses a IBM chip and the Reply the Cirrus Logic CD-GL 5426 chipset
which is VESA compatible.
IBM also has a SVGA card for servers. As such, it maxes out at
256 colors.
A note about XGA/2, it is not VESA compatible at the hardware level...there
are drivers that allow it to be VESA compliant but these drivers freak
out many pieces of commercial software...be advised.
Also on the high end, I know of Matrox making some in the $1k + range
that have 1MB+ of VRAM but I have yet to hear of the performance or to
run into someone who has purchased one. Also RasterOps Colorboard
1024MC can display 1024x768x16.7M (no modes above 1024x768) with the 3MB
of VRAM it has, but it is slow compared to other video cards and expensive.
Also I am curious as to the specs of the IBM Image I Adapter which is about
$2.7k with 3MB VRAM for 1280x1024x256 color support.
ATI has the Ultra Pro 2MB a 2MB VRAM card with a 32 bit accelerator.
This card had be found for as low as $250 (retails for ~$500)[prices as
of 1996]. I am curious to its performance as the 64 bit versions
are top in their class, but for just the ability to get greater color depth
the 2MB card is worth it. Be advised that ATI has the habit of constantly
changing its drivers so compatibility issues may arise and a downtime for
new drivers may be upon you. It uses the Mach32 chipset so is widely
supported, NT 4.0 supports this also.
Q) 4.7 How can I add
a CD-ROM drive to my PS/2?
Most of the time an external CD-ROM can be added if you have a SCSI
card with no problem. Internal CD-ROMs can be added to any PS/2 with
a 5 1/4" bay, some that have internal 5 1/4" bays (60/65SX/80) can use
special bezels to vertically mount a CD-ROM. In these cases caddy-type
drive are mandatory. The drivers needed are usually dependant on which
SCSI card you use so contact the manufacturer if CD drivers were not supplied.
Use the cheap AT Drive rails for 85 or 95 installations. You have to
shorten the rails a bit on both ends. You don't need a CD-ROM bezel for
these, as it's a close fit. The drive will be retained up front by the
drive retainer. If you want a professional look, then get the bezel.
For 56, 57, 76, or 77 installations, the CD-ROM bezel keeps the CD from
sliding out of the case (tis true!)
Q) 4.7a Jumper Settings
for a CD-ROM
Usually, the CD-ROM is jumpered as ID 0, that is NO jumpers
on any "IDx" pin. It's a relatively slow device on the SCSI chain. IF you
have a multimedia system, you may want to set the CD to ID3. You MUST have
"Parity" jumpered. IBM SCSI devices require parity (some Apple CD-ROMs
do not have parity, and cannot be used).
Leave PRV/ALW alone. If you cannot eject a CD, check this jumper.
Leave "Test" unjumpered. If the CD is the last device on the SCSI cable,
jumper "Term". This assumes that you have the terminating resistors (SIPs)
or the termination is built-in. If it's an older model that uses discrete
terminators, and they're lost, either get an in-line terminator or put
the CD in the middle of the SCSI cable where it doesn't need termination.
Q) 4.7b Installing DOS/W9x
on a CD-ROM w/IBM SCSI Controller
You need the IBM CD-ROM driver and ASPI4B.sys to do this.
Two places to get info are HERE
which has Dos and W95 autoexec.bat and config.sys examples, and HERE
which has the more involved method.
Do you need IBMCDROM.SYS
and ASPI4B.SYS? This way you can get the device drivers and edit the
autoexec and config yourself without finding or creating a 720KB floppy...
Q) 4.8 How can I build
a Multimedia PS/2?
You can build a multimedia PS/2 the same way as a normal PC. The
exceptions are sound cards. As it stands now you must use the SB-pro
or clone for DOS and the Audiovation/A or equivalent for windows.
Any SCSI CD-ROM should work with a SCSI card and any big monitor will work.
Reply Technologies, Matrox, and ATI all make video cards for SVGA, some
have up to 3MB of RAM. Also any speaker setup will work with the soundcards
providing they have they same connectors (usu. RCA or mini RCA).
Other than that you will want a fast hard drive and probably a 33 MHz or
faster machine.
Here is an example:
PS/2 Model 80-A21
Cyrix Cx486DRx2-50 Processor upgrade with 33D87 NDP.
Mag DX15F Monitor
Reply Technology Video Adapter
Plextor 4x CD-ROM (internal mounted)
Piper or ChipChat SB-Pro sound card
Audiovation/A sound card
Seagate ST-3600N SCSI hard drive
Future Domain MCS-600 SCSI controller.
Sony Speakers
CH Game Card III
Generic PC joystick
Q) 4.9 How can I get
sound effects in DOOM?
[From: cousinad@aol.com (Cousin AD)]
Option #1:
Choose all the WRONG settings for the DMA, IRQ and I/O address.
Save settings and play... You may still need to re-boot one time
before this works.
Option #2:
Choose the wrong setting for the I/O Address (use the correct settings
for the IRQ & DMA).
The above worked for me, but I found problems setting-up for modem play...
I figured, hey, you can't have it all... Then I got another suggestion
that really solved the problem...
Option #3:
Choose all the CORRECT settings for the DMA, IRQ and I/O Address.
Exit set-up and choose yes to "Save settings before exit." Then,
before starting DOOM, open the file DEFAULT.CFG in an ASCII text editor
(MS-DOS "EDIT" for instance). Change the "SND_SBPORT" line from 544
to 220 or 240, depending on your SoundBlaster MCV configuration.
Save the DEFAULT.CFG file and start DOOM...
Q) 4.10 How can I
make my PS/2 Model 90/95 a Pentium 180/200MMX machine?
Warning! I have seen reports of
complex failure and death resulting from this mod or similar ones. The
cause is the upgrade CPU is trying to suck enough power from the Voltage
Regulator. Problem is, the traces or VR don't have the extra oomph needed.
I had a Terminauter interposer complex start to go flakey after six or
so months.
A possible solution is a Madex interposer. It has the
external power tap so it can drive the cpu from the power supply.
First it is going to always be a P180MMX as the clock tripling runs
at 3x60 and there is no easy way to modify this, although if a budding
Electrical Engineering student wants to do so I am sure the list would
love a P233MMX version.
Secondly, you must use the Overdrive version of the P180MMX or P200MMX
as the non-Overdrive version do not work properly in this capacity.
Also note the P90 version of the Type 4 complex is needed. Contrary
to popular belief all of the Type 4 complexes are as different from each
other as they are to the Type 1, 2, and 3 complexes (as well as each different
kind of those). You need the "Y" upgrade of the Type 4 complex, announced
Oct 1994, and known as IBM Part Number/FRU# 06H3739 or 19H1027 (and
a few other crossreferenced numbers).
The "P" and "Q" complexes use a 497 cache controller, which is unfortunately
incompatible with Overdrive CPUs. Some experiments have been made with
varying success.
These go for about as much as a small third world country (or half the
continental United States if purchased directly from IBM). So make
sure you can afford to lose this board should any of the below modifications
screw up your processor board or PC. If performed as outlined and
no mistakes are made it is a totally reliable modification and brings your
machine to the front of the pack. Remember most applications peak
out at 200-233 MHz Pentium speeds and the PII's are really only useful for
games, high-end graphics, and high-end multiuser server applications.
The complete breakdown with pics is available HERE.
Disclaimer
Modifying your processor complex with these instructions will void any
remaining warranty and may cause irreparable damage resulting in a non-functioning
processor complex if performed incorrectly. There are no warranties expressed
or implied. Modify at your own risk. (Manufacturers warranty on newly purchased
PC Server 500's was usually three years depending on country of purchase.
Check your warranty information if concerned or unsure. Optional service
contracts may have altered or extended your period.)
Introduction
The following instructions can assist you in modifying the 90 MHz Pentium
processor complex that was originally manufactured in the IBM PC Server
500 System390 so that you can use the Pentium® Overdrive 180 MHz with
MMX chip. If you unplug the Pentium® 90 MHz chip from the complex and
plug in the 180 MHz Pentium® Overdrive without this modification, you
will experience two problems:
I. The electric fan that cools the Pentium® Overdrive chip will
not have power to turn the blades. You will 'cook" (burn out) the Pentium®
Overdrive due to inadequate cooling. (The 90 MHz Pentium® chip uses
a heat sink instead of an electric fan.)
2. Without providing 5 volts to the overdrive chip, the chip will run
at about 25 MHz which is slower than the installed 90 MHz chip.
Directions
* Locate and have a working reference diskette for the PC Server 500
available.
You will need it if you use a different processor complex board
than the one currently installed. You should not need it if you remove,
modify, and replace the same processor complex board that is currently
installed. Better to locate and have it ready than to not have it.
* The processor complex does not use a ZIF (zero insertion force) socket
for the Pentium® processor. The old 90 MHz processor must be carefully
removed. (A good quality jewler's screwdriver was useful to the author
in starting to pry the chip from the socket and then working around the
perimeter of the chip increasing in small increments. Insert the tip of
the screwdriver between the socket and the chip. Use only the socket surface
and not other chips or edges on the board as fulcrums for prying.)
* Solder an insulated wire from the +5 volt regulator to the two unused
pins on the Pentium® 'internally no-connect'.
* The two pins are technically labeled AN01 and AN03. There are no
labels visible that say AN01 or AN03.
* After the wire has been soldered to all three points and allowed
to cool, carefully align all pins of the new processor to their
respective holes taking note of the key (missing pin on one corner). Carefully
push the new processor into the holes. The new processor pins may be longer
than those of the old processor and therefore there may be a gap between
the bottom of the new processor and the socket surface.
* Reinsert the processor complex into the PC Server and reconnect the
signal wire.
Power on the server and assure that the fan on the Pentium Overdrive
processor is turning (a flashlight aimed at the fan when power is applied
will probably be necessary).
* You will note that the LED display on the front of the PC Server
500 will say "60 MHz" instead of "90 MHz." This is normal.
Modify at your own risk! Modification will void warranty.
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