Intel Overdrive Processors
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Overview
Starting in the 486 era, many Intel based PC systems
were sold with the promise of future upgrade chips that would simply plug
in and significantly speed up the system. "Future Proof," it was often
referred to. There were several families of Intel Overdrive Processors
produced starting with 486 (sockets 1, 2 and 3), Pentium (sockets 4 and 5)
and Pentium Pro (socket 8).
In the opinion of this collector, many Overdrive chips promised a lot more
than they delivered.
Intel Overdrive Processors were always intended to be fool proof. They were designed to just be installed and work. You didn't need to change any jumper settings on the board or do anything in the BIOS.
The rarity rating
Each chip is rated as to how rare it is. This is
pretty much a rating of how hard it is to obtain a chip (mainly using eBay
or chip collecting sites).
One dot indicates a common chip that
you could buy on eBay today.
Chips
with two dots are not really common, but still quite easy to find.
Three dots indicates a chip that is not easy to
find, but not all that hard either.
Chips with four
dots are those that are very seldom available for sale.
Five dots indicates chips that are known from only a handful of examples.
486 OverDrive part numbering.
When Intel introduced the 486 OverDrive processors in
1992, they used a confusing part numbering system. Each chip was marked
the same as the chip it was intended to replace with 'ODP' (OverDrive
Processor) at the beginning. So if you had a 486SX-25, you bought the
ODP486SX-25. If you had a DX-33, you bought the ODP486DX-33. This was
rather misleading as all the OverDrive processors were clock doubled with
built in co-processors - ie they were DX2 processors. So the ODP486SX-25
was actually a DX2-50.
Then there was a further complication - were you
going to plug your new Overdrive processor into an upgrade socket on your
motherboard or were you going to replace your original CPU? Overdrive
processors intended for upgrade sockets had an extra pin and were marked
as 'ODP.' Processors intended to replace the original CPU were marked as
'ODPR' the R standing for replacement. The extra pin on the ODP versions
was used to disable the original CPU and also to prevent the processor
from being installed into the wrong socket. Once an ODP processor was
installed in the upgrade socket, the original CPU was disabled and if it
was not soldered to the board, could be removed.
In early 1994, Intel dropped the original part numbering system and labelled the processors with their actual clock speed. The ODP and ODPR distinction was retained. Shortly after this change the SX and DX distinction was also dropped, with all chips marked as DX.
The SX series of Intel 486 OverDrive Processors.
ODP486SX-20
Sspec: SZ699 B1
Manufactured: Week 13, 1993
Rarity:
ODP486SX-20
Sspec: SZ675 A2
Manufactured: Week 13, 1993
Rarity:
ODP486SX-25
Sspec: SZ676 A2
Manufactured: Week 31, 1992
Rarity:
ODP486SX-25
Sspec: SZ800 B1
Manufactured: Week 27, 1993
Rarity:
ODP486SX-25
Sspec: SZ874 V3.0
Manufactured: Week 10, 1994
Rarity:
SX2ODP50
Sspec: SZ901 V1.0
Manufactured: Week 17, 1994
Rarity:
ODP486SX-33
Sspec SZ801 B1
Manufactured: Week 38, 1992
Rarity:
ODP486-33
Sspec Q695 ES B1
Manufactured: Week 29, 1992
Rarity:
Somewhat misleadingly named as all of them are clock-doubled DX chips
with built in co-processors. Overdrive processors hadn't yet reached
their height of popularity by the time Intel changed the partnumbering
in early 1994 system so all of these chips remain rather rare.
The DX series of Intel 486 OverDrive Processors.
ODPR486DX-25
Sspec: SZ697 B1
Manufactured: Week 38, 1992
Rarity:
ODPR486DX-25
Sspec: SZ877 V3.0
Manufactured: Week 9, 1994
Rarity:
ODP486DX-33
Sspec: SZ698 B1
Manufactured: Week 52, 1992
Rarity:
ODPR486DX-33
Sspec: SZ878 V3.0
Manufactured: Week 8, 1994
Rarity:
ODP486DX-33
Sspec: SZ802 B1
Manufactured: Week 24, 1994
Rarity:
Overdrive processors were
gaining in popularity by early 1994. Like the SX series, the partnumber
is a bit misleading as they are clock-doubled (DX2) processors. The
DX-33 is much more common than the DX-25.
The DX2 series of Intel 486 OverDrive Processors.
DX2ODPR50
Sspec: SZ908 V3.0
Manufactured: Week 47, 1994
Rarity:
DX2ODPR50
Sspec: SZ934 V4.0
Manufactured: Week 10, 1995
Rarity:
DX2ODP50
Sspec: SZ902 V3.0
Manufactured: Week 24, 1994
Rarity:
DX2ODP50
Sspec: SZ932 V4.0
Manufactured: Week 35, 1995
Rarity:
DX2ODP50
Sspec: SZ932 V4.0
Manufactured: Week 5, 1995
Rarity:
DX2ODPR66
Sspec: SZ904 V3.0
Manufactured: Week 44, 1994
Rarity:
DX2ODPR66
Sspec: SZ935 V4.0
Manufactured: Week 16, 1995
Rarity:
DX2ODP66
Sspec: SZ903 V3.0
Manufactured: Week 15, 1994
Rarity:
DX2ODP66
Sspec: SZ933 V4.0
Manufactured: Week 20, 1995
Rarity:
By late 1994, the Overdrives were very
popular. While designed as an upgrade chip, many were sold already
installed in new PCs. The DX2ODPR66 was the most popular of them all.
The DX4 series of Intel 486 OverDrive Processors.
DX4ODPR75
Sspec: SZ925 V1.0
Manufactured: Week 43, 1994
Rarity:
DX4ODPR75
Sspec: SZ958 V1.1
Manufactured: Week 52, 1994
Rarity:
DX4ODP75
Sspec: SZ956 V1.1
Manufactured: Week 22, 1996
Rarity:
DX4ODP100
Sspec: SZ957 V1.1
Manufactured: Week 18, 1995
Rarity:
DX4ODPR100
Sspec: SZ926 V1.0
Manufactured: Week 35, 1994
Rarity:
DX4ODPR100
Sspec: SZ959 V1.1
Manufactured: Week 5, 1995
Rarity:
These processors run a 3x multiplier.
So why are they not marked as DX3? Apparently Intel was going to release
a series of processors with a 2.5x multiplier. These would have been
marked as DX3. These chips were never produced, but the clock tripled
processors remained marked as DX4. These were the last of the 486
Overdrive processors. The Pentium had been released by the time these hit
the market, so while popular, they are not as common as the 66Mhz
Overdrives.
Pentium OverDrive Processors for 486
PODP5V63
Sspec: SZ953 V1.0
Manufactured: Week 14, 1995
Rarity:
PODP5V63
Sspec: SZ953 V1.0
Manufactured: Week 14, 1995
Rarity:
PODP5V63
Sspec: SZ990 V1.1
Manufactured: Week 30, 1995
Rarity:
PODP5V63
Sspec: SZ990 V1.1
Manufactured: Week 30, 1995
Rarity:
PODP5V63
Sspec: SZ990 V1.1
Manufactured: Week 30, 1995
Rarity:
PODP5V63
Sspec: SU013 V2.1
Manufactured: Week 1, 1996
Rarity:
PODP5V83
Sspec: SU014 V2.1
Manufactured: Week 44, 1995
Rarity:
PODP5V83
Sspec: SU014 V2.1
Manufactured: Week 44, 1995
Rarity:
PODP5V83
Sspec: SU014 V2.1
Manufactured: Week 42, 1996
Rarity:
PODP5V83
Sspec: SU014 V2.1
Manufactured: Week 42, 1996
Rarity:
PODP5V83
Sspec: SU014 V2.1
Manufactured: Week 40, 1997
Rarity:
PODP5V83
Sspec: SU014 V2.1
Manufactured: Week 36, 1996
Rarity:
These processors promised so much and delivered so little. Many 486 systems were sold with the capability to upgrade to a Pentium in the future. By the time the 63Mhz version was released in February 1995, the 486 era was in its declining phase. The price of the chips was so high that for not too much more you could upgrade the motherboard and cpu and get a real Pentium (which would also give a much greater speed boost). The 83Mhz version was not released till 8 months later and it wasn't much better, barely keeping up with Intel's own 486DX4. On the plus side, the Pentium Overdrive processors gave you access to the Pentium instruction set and its very good co-processor.
The processor itself is a Pentium core modified to interface with the 486 bus. Its bus was 32bit, half that of the Pentium and it had a larger L1 cache to compensate. It runs on 3.3 volts with a built in voltage regulator to take the 5v supply from the motherboard. The fan is powered from the socket.
Intel did have plans to release a 3.3V Pentium
Overdrive for 486. They would have run only in socket 3 or the unreleased
socket 6 (which would have been 3.3V only). It appears that development
got as far as a mechanical sample to supply to PC system manufacturers to
test clearances above the socket before being cancelled.
It appears that these processors sold poorly. There are three different sspecs of the 63Mhz versions and all three are quite hard to find today. The 83Mhz sold better, but supply greatly exceeded demand and it is easily obtainable today, even brand new in its box. While not very successful, the Pentium Overdrive for 486 found its niche in proprietary OEM computer systems. These systems usually cannot have their motherboards replaced so the Pentium Overdrive processor was the only upgrade option.
Here is where Intel could have done much better. A
Pentium Overdrive running at 133Mhz (like AMD's X5) or even 166Mhz would
have beaten any socket 3 competition and been a very popular upgrade
chip! It didn't happen of course, because Intel didn't want such a chip
eating sales of its Pentiums (real ones, not Overdrive ones!)
Pentium OverDrive Processors for socket 4 Pentium (P5)
PODP5V120
Sspec: SU080 V1.0
Manufactured: Week 50, 1995
Rarity:
PODP5V120
Sspec: SU080 V1.0
Manufactured: Week 50, 1995
Rarity:
PODP5V133
Sspec: SU082 V1.0
Manufactured: Week 39, 1996
Rarity:
PODP5V133
Sspec: SU082 V1.0
Manufactured: Week 39, 1996
Rarity:
PODP5V133
Sspec: SU082 V2.0
Manufactured: Week 44, 1997
Rarity:
PODP5V133
Sspec: SU082 V2.0
Manufactured: Week 44, 1997
Rarity:
PODP5V133
Sspec: SU082 V1.0
Manufactured: Week 39, 1996
Rarity:
Relatively unknown, these Overdrives
were one of the very few CPU upgrade options for socket 4 based Pentiums.
They ran a 2x multiplier and would double the clock speed of the original
chip. Nearly all of them sold were rated at 133Mhz and the same chip was
used for both 60 and 66Mhz systems - the chip just ran at 120Mhz on a
60Mhz system. (Of course, if you had a Pentium 60 and knew a little bit
about computers, you could change the bus speed to 66 and get that extra
13Mhz out of your new Pentium Overdrive!)
It appears that Intel initially produced socket 4
Pentium Overdrive processors at both 120 and 133Mhz and soon after decided
to just use the 133Mhz part as the upgrade chip for both 60 and 66Mhz
systems. The 120Mhz version is as rare as hens teeth and only a handful
have been seen.
Pentium OverDrive Processors for socket 5 Pentium (P54)
PODP3V125
Sspec: SU081 V1.0
Manufactured: Week 12, 1996
Rarity:
PODP3V125
Sspec: SU081 V1.0
Manufactured: Week 12, 1996
Rarity:
PODP3V150
Sspec: SU083 V1.0
Manufactured: Week 7, 1996
Rarity:
PODP3V150
Sspec: SU083 V1.0
Manufactured: Week 30, 1995
Rarity:
PODP3V166
Sspec: SU084 V1.0
Manufactured: Week 4, 1996
Rarity:
PODP3V166 (fake)
Sspec: SU084 V1.0
Manufactured: Week 42, 1996
Rarity: N/A
PODP3V125
Sspec: SU081 V1.0
Manufactured: Week 44, 1995
Rarity:
PODP3V166
Sspec: SU084 V1.0
Manufactured: Week 42, 1996
Rarity:
PODP3V166
Sspec: SU084 V1.0
Manufactured: Week 42, 1996
Rarity:
A80502166 (fake)
Sspec: SU072
Manufactured: Week 12, 1996
Rarity: N/A
A80502166 (fake)
Sspec: SU072
Manufactured: Week 12, 1996
Rarity: N/A
Like all the Overdrive processors, these are designed to be foolproof. On the back of each box is a diagram telling you which chip to buy depending on the clock speed of your current Pentium. Then all you have to do is remove the existing chip, drop in the Overdrive and it should just work. No changing motherboard or BIOS settings.
This series of Pentium Overdrive processors is
intended for socket 5 systems. These systems have a maximum speed of
133Mhz (2x 66). The Overdrive processors use a 2.5x multiplier and in the
opinion of this collector, would not have provided that much of a speed
boost. More memory or a faster hard drive would have been a better
upgrade. All three are more or less the same chip. The speed it runs at
is dependent on the system's bus speed. They would have worked best with
the slowest Pentium processors - 75, 90 and 100Mhz. If your system was
120Mhz or 133, these chips would have provided very little improvement -
you would do much better with the MMX Overdrives (below). Probably
because of this, these Overdrives are not that common today.
As with all Pentium Overdrives, the fan is powered from the CPU socket.
The fake PODP3V166 shown here is an example of a
widespread practice in the days - taking a slower chip and remarking it as
a faster one and selling it for $100 more. This fake is likely a
PODP3V150 underneath. Fakes can be identified by the poorer quality
engraving and signs of grinding away or painting over the original
markings. Remarked chips very rarely had engravings as good as the
original. The second fake is much easier to identify - it is an Overdrive
marked as a standard Pentium 166!
Pentium MMX OverDrive Processors for socket 5 Pentium (P54)
PODPMT60X150
Sspec: SL24V V1.0
Manufactured: Week 18, 1997
Rarity:
PODPMT60X150
Sspec: SL24V V1.0
Manufactured: Week 18, 1997
Rarity:
PODPMT66X166
Sspec: SL24W V1.0
Manufactured: Week 9, 1997
Rarity:
PODPMT66X166
Sspec: SL24W V1.0
Manufactured: Week 9, 1997
Rarity:
PODPMT66X166
Sspec: SL24W V1.1
Manufactured: Week 32, 1997
Rarity:
PODPMT66X166
Sspec: SL2KB V2.1
Manufactured: Week 41, 1997
Rarity:
PODPMT60X180
Sspec: SL2FE V2.0
Manufactured: Week 46, 1997
Rarity:
PODPMT60X180
Sspec: SL2RL V2.1
Manufactured: Week 8, 1998
Rarity:
PODPMT66X200
Sspec: SL2FF V2.0
Manufactured: Week 44, 1997
Rarity:
PODPMT66X200
Sspec: SL2FF V2.0
Manufactured: Week 44, 1997
Rarity:
PODPMT66X200
Sspec: SL2RM V2.1
Manufactured: Week 31, 1998
Rarity:
PODPMT60X150
Sspec: SL24V V1.0
Manufactured: Week 31, 1998
Rarity:
PODPMT66X166
Sspec: SL2KB V2.1
Manufactured: Week 31, 1998
Rarity:
PODPMT60X180
Sspec: SL2RL V2.1
Manufactured: Week 31, 1998
Rarity:
PODPMT66X200
Sspec: SL2RM V2.1
Manufactured: Week 31, 1998
Rarity:
PODPMT66X166
Sspec: SL2KB V2.1
Manufactured: Week 31, 1998
Rarity:
These were the best of the Pentium
Overdrive Processors. Still intended mainly for socket 5 systems, these
processors gave faster speed and also added MMX instructions, which gave
an additional tiny speed boost. Like the non-MMX Overdrives, these chips
are drop in 'guaranteed to work, no worries mate' type upgrades. Only
this time, there were more options. If you had a Pentium 100, you could
upgrade to the 166MMX Overdrive or go the full mile and get the
blisteringly fast (and probably quite expensive) 200MMX Overdrive. If you
had a Pentium 75, well, sorry, the best you can get is 125Mhz using the
150Mhz chip. (or as always, if you knew how, you could change the bus
speed and bust the wallet on the 200Mhz!). These Overdrive processors
were the best CPU upgrades available for socket 5. And yes, they would
work in socket 7 systems, but the improvement would hardly be worth the
cost. They would probably have been an OK upgrade for early socket 7
boards that could not supply the voltages required for later standard
Pentiums. Later boards you could just drop in a Pentium 233MMX or a
faster Cyrix or AMD chip.
Here is another place where Intel dropped the ball. In this collector's opinion, a 300Mhz Pentium Overdrive would have been a very popular chip, especially if you could run it at a 75Mhz bus. A chip with internal L2 (like an AMD K6-III) would have been an outstanding performer. Of course, such a chip would hurt the sales of Intel's brand new cash cow, the Pentium II so it would be more accurate to say that Intel didn't drop the ball, they put it down.
The 180 and 200Mhz Pentium MMX Overdrives were quite
popular and are easily obtained today. The 166Mhz version is not as
common and the 150 is as rare as hens teeth.
Pentium II OverDrive Processors for socket 8 Pentium Pro (P6)
PODP66X333
Sspec: SL2KE V1.0
Manufactured: Week 20, 1999
Rarity:
PODP66X333
Sspec: SL2KE V1.0
Manufactured: Week 20, 1999
Rarity:
PODP66X333
Sspec: SL2KE V1.1
Manufactured: Week 20, 1999
Rarity:
PODP66X333
Sspec: SL2KE V1.1
Manufactured: Week 20, 1999
Rarity:
PODP66X333
Sspec: SL3EA V1.1
Manufactured: Week 37, 1997
Rarity:
PODP66X333
Sspec: SL3EA V1.1
Manufactured: Week 37, 1997
Rarity:
PODPMT60X180
Sspec: SL2FE V2.0
Manufactured: Week 46, 1997
Rarity:
The only Overdrive processor for socket 8 systems, the Pentium II Overdrive processor provided a substantial improvement for Pentium Pro systems. Depending on the bus speed of 60 or 66Mhz the Overdrive ran at 300 or 333Mhz. It is essentially a Pentium 2 chip combined with 512k of full speed level 2 cache. In the photo of the chip without the heatsink above, the small dark chip is the CPU while the larger green chip is the cache. This is the same cache chip used in the Pentium II Xeon. The Pentium II Overdrive was enormously popular and as such is easily obtainable today - although they are often still quite expensive even second hand. Retail boxed chips (SL2KE) had the built in heatsink/fan while the OEM versions (SL3EA) just had a heatsink and also lacked the logo on the underside of the processor.
The vast majority of these processors are the retail
version. The OEM variety is quite hard to find.
Chips wanted for collection
Intel ODP486SX-20 SZ635
Intel ODP486SX-20 SZ873
Intel ODP486SX-25 SZ861
Intel DX4ODP75 SU001
Pentium Overdrive 200MMX V2.8 (fake)
