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#Post#: 11--------------------------------------------------
Intel CPU's
DIR By: Mr Horse
Date: December 17, 2017, 2:12 pm
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Socket 1,2,3
Intel CPU removal tool for Low insertion force (LIF) sockets
First introduced in 1989 the Intel 486 CPU originally fit into a
168-pin PGA socket. After the introduction of the 486SX (and
rebranding of the 486 to 486DX) Intel introduced "Socket 2"
which was included an extra row of pins around the 168-pin
socket that was supposed to be an upgrade path to Pentium
technology. However, the main advantage of using the new socket
was "Zero Insertion Force" or ZIF technology that allowed the
CPUs to be removed easily without any tools. Socket 3 was more
or less the same as Socket 2 except that it optionally supported
3V operation. The extra row of pins used in both socket were
only used for extra voltage and grounding. The Pentium (POD63,
POD83) upgrades didn't come out until 1996, and ironically
didn't fully work in the majority of older systems that were
claimed to support them. With the exception of the Pentium
Overdrives, any 486 CPU can work in any 486 Socket as long as a
voltage regulator is used with the 3V chips.
The first generation of intel 486 chips were 5V and made at 1
micron with 8kb of write-through L1 cache. The second generation
were normally 0.8 micron. 486DX2s support clock doubling
(40,50,66MHz). 486SX has the math coprocessor removed. The 487SX
was advertised as a math-coprocessor for a 486SX but was
esentially a full blown 486DX with a slightly modified pinout.
The third generation of Intel CPUs were 0.6 micron and ran at
3.3V. The 3V version of the 486DX2 retained the 8kb write
through cache. The Intel DX4 introduced clock tripling, despite
having a name which implies clock quadrupling. Additionally, it
sported 16kb writethrough or writeback cache (depending on the
model), as well as some ALU enhancements used in Pentium chips.
Although the DX4 was only produced in 75 and 100MHz versions,
the 100MHz part normally ran about as fast as an am486DX4-120.
Intel DX4s had a multiplier jumper and could be set in either 2X
or 3X modes. In some cases it is possible run them on a 50MHz
bus (in 2X mode). Intel documentation and some motherboards
mention support for a 2.5X multiplier setting, however this was
removed before the design was finalized. The 2.5X mode was
originally meant to be used in a 486DX3-63,83 (2.5X clock) but
these were deemed to be unmarketable.
In addition to the standard 486 chips, Intel also marketed a
separate line of "Overdrive" chips. The first generation of
overdrives weren't really necessary as they were merely 486DX2s
with fancy heatsinks and a slightly modified pinout. Before ZIF
sockets became common, most 486 boards had second special "487"
or "Overdrive" sockets to take these overdrive chips. However,
they all work fine in a standard 486 socket with a few changes
to the motherboard jumpers. DX4 overdrives included integrated
VRMs for use on older 5V motherboards, however they were
multiplier locked.
486DX/4 100MHz Overdrive
Socket 4
Pentium 66 (Socket 4)
Socket 4 was released around 1993 and housed the very first real
Pentium processor. Very few different CPU's have been made to
fit this socket, which is limited to the Pentium 60MHz, the
Pentium 66MHz and the obscure Pentium Overdrive which ran at
either 120MHz or 133MHz. Because of the limited variety of CPU's
manufactured for this socket and the limited speed options these
motherboards provided, Socket 4 is a far less flexible platform
when compared to Socket 3 or Socket 7. Socket 4 supported the
then new 60MHz FSB and 66MHz FSB (even though some Socket 4
motherboards were made that had slower FSB's like 50MHz and
40MHz). Usually Socket 4 motherboards were fitted with ISA and
PCI slots, though some VLB slotted Socket 4 motherboards were
made. Socket 4 motherboards used either EDO or FPM memory
modules and the memory modules had to be fitted in pairs where
in it's predecessor, single modules were used. This was because
Socket 4 was the first x86 motherboard that had a 64-bit memory
bus (486 and earlier used a 32-bit, or a 16-bit memory bus).
All Socket 4 motherboards were made as AT motherboards or as
proprietary boards. No ATX Socket 4 motherboards were ever made.
No AGP slotted Socket 4 motherboard was ever made.
Socket 5,7
Pentium Classic
Classic Pentium CPUs have a wide variety of speeds, from 75 to
200 MHz. They are supported by literally any Socket 7 chip set
and proved to be fine performers. Pentium Classic is a good
choice for Socket 7 Build, especially for beginners. They are
easy to find and cost next to nothing.
Pentium MMX
Pentium 166 MMX
Pentium MMX CPUs arrived in 166, 200, 233MHz versions (66MHz
x2.5, x3.0, x3.5).
Note that mobile Pentium MMX processors ran at up to 300Mhz
speed, however, they had a different core (Tillamook) and
usually a different packaging. There are Tillamook Pentiums in
the same Socket 7 package as the later Pentium MMX chips, but
it's proven difficult to get these running in desktop boards as
the system will often not boot correctly without disabling the
CPU cache. Possibly these chips can run with it's caches all
enabled using a motherboard with Intels own 430TX chipset, but
finding details about this is sketchy
Comparing to Pentium Classic, they have different core (P55C)
with lesser 0.28 µm process. L1 cache was doubled (32KB vs
16KB). A new set of instructions called MultiMedia eXtensions
was introduced, although the software to use them started to
appear only by the time Pentium MMX processors were severely
outdated.
Pentium MMX processors are supported by later Socket 7
motherboards with split rail voltage. Not every motherboard will
accept such a CPU.
Overall Pentium MMX 233 can be considered the best choice of
authentic CPU for a socket 7 system. When overclocked to 262MHz
or further, it provides exceptional performance no other Socket
7 CPU can match. Pentium MMX CPUs are harder to find than
classic Pentiums, but they are still quite cheap.
Pentium Overdrive and Pentium MMX Overdrive
These were split-rail processors mounted on a package together
with a VRM and in essence were Intel's own upgrade chips. They
were designed to be plug-in replacements for motherboards that
used the classic Pentium. They have a small heatsink with a fan
and if the fan fails or is removed, the CPU will downclock to
using a 1x multiplier in order to prevent it from overheating
(only in case of the Overdrive for the 486 socket). As these
CPU's (other than the 1x multiplier in earlier versions) are
multiplier-locked, these CPU's aren't commonly used for
retro-rigs
Slot 1
Pentium II
The first CPU made available for Slot 1. It featured a
'cassette' containing a small PCB with the CPU die soldered onto
it along with 2 cache chips for a total of 512KB of L2 cache.
The cache chips ran at half the CPU clock speed though, which
was a departure from Intels Pentium Pro where the L2 cache ran
at the same speed as the CPU.
The Pentium II was made in 2 different versions. First came the
Klamath, running at speeds from 233MHz up to 300MHz. These
processors ran fairly hot for their time (up to around 40W), but
an interesting fact for someone building a retro rig is the fact
that most of these still had their multiplier unlocked. The
second version was basically a die-shrinked Klamath, called the
Deschutes, which was made in speeds of 266MHz up to 450MHz. The
Deschutes is typically the prefered choice over Klamath, mostly
because it offers more performance while producing less heat
while having virtually no drawbacks except for most
Deschutes-based Pentium IIs being multiplier-locked
Celeron
The Celeron for Slot 1 was the very first Celeron ever made and
was designed to fill in the gap created by the introduction of
the Pentium II while at the same time Intel left it's budget
users with the aging Pentium MMX 233.
2 Celeron cores were made for Slot 1.
The first one was the Covington, which was basically a Pentium
II without it's cache chips and the lack of any L2 cache had
such a bad impact on performance that Intel quickly released a
second core, Mendocino, featuring 128KB L2 cache. Only 2 speed
grades of Covington were made, running at 266MHz and 300MHz
before it was quickly replaced by Intels next Celeron
incarnation. Mendocino was made available from 300MHz up to
433MHz when Mendocino moved back to a socketed solution
(becoming Socket 370) Even though the Mendocino had only a
quarter of the cache of the Pentium II, it ran at full speed
instead of Pentium IIs half speed and had performance rather
similar to the Pentium II.
Pentium III
The Pentium III was Intels successor of the Pentium II. By this
time all Slot 1 CPUs were multiplier locked (except for some
engineering samples perhaps). The Slot 1 Pentium IIIs came in 2
different variants. The first one was called Katmai and ran at
speeds from 450MHz to 600MHz and this Pentium III was very
similar to the Pentium II it was supposed to succeed. The Katmai
could be considered a "Pentium II+" as it's main new feature was
the addition of SSE instructions. Because the Katmai also had
it's cache chips off-die, it still needed to be mounted on a
small PCB along with it's cache chips.
The second and final variant of the Slot 1 Pentium IIIs was the
Coppermine. The Coppermine featured 256KB on-die cache which was
only half the amount of cache the Katmai had, but instead of
running at half the speed of the CPU, the Coppermine had it's
cache run at full speed, thereby increasing it's performance
even though it had only half the cache.
The Coppermines also ran significantly cooler compared to Katmai
and because the absence of any off-die cache, Intel quickly
moved back to a Socketed solution for Coppermine.
Today: Slot 1 mainboards are a popular base for building a retro
rig these days, mostly because of their overall good stability,
the good availability of Slot 1 boards and their good
compatability with other hardware, their good range of different
CPUs which could be set up to running all the way from around
100MHz (when underclocked) all the way to 1400MHz (and possibly
even higher when overclocking), their good performance and
perhaps mostly because of Intels BX chipset which was made for
Slot 1. Also BX boards are relatively easy to set up.
Socket 370
Pentium 3 1400MHz
Socket 370 was released on the 4th of January 1999 and was
originally made as a budget CPU socket compared to Intel's
higher-end Slot 1 solution. Later it became Intel's main CPU
Socket until the release of the Pentium 4, after which it moved
to the budget end of the market again before being phased out
altogether. A wide variety of CPU's exist for this socket,
ranging from the 333MHz Celeron (with Mendocino core) all the
way to the Pentium 3 1400MHz (with the 512 KB L2 cache version
also being known as Tualatin-S). The Tualatin-S was also very
popular for servers because of their low power consumption.
VIA also made a variety of CPU's for this socket, though
compatibility is somewhat sketchy.
As this CPU socket went through a couple revisions, not all
Socket 370 CPU's will work in any given Socket 370 motherboard,
even though they will mechanically fit. Generally speaking there
are 3 different types of motherboards using this socket:The
early Celeron Mendocino-only motherboards (usually limited to a
66MHz FSB), the Coppermine capable motherboards (having a
maximum FSB of either 100MHz or 133MHz) and the Tualatin capable
motherboards. Sometimes Tualatin capable motherboards have their
CPU socket colored blue instead of the usual white.
Be wary when mounting a CPU cooler onto a CPU which has an
Integrated Heat Spreader, as the taller CPU will make mounting
the CPU cooler more difficult and may even cause the tabs on
either side of the CPU socket to snap due to the increased force
applied by the CPU cooler.
To prevent usage of newer CPU's in older motherboards, Intel
switched a couple pins around to prevent operation of Coppermine
CPU's in the earliest Celeron-only boards and Intel repeated
that trick when it started manufacturing Tualatin CPU's. This
prevented the use of later chips in older motherboards, even if
the right (lower) voltage could be supplied by the motherboard.
Usually Socket 370 boards have AGP slots. The older ones have an
AGP 2x (3.3V) and the newer ones have a universal 1.5V AGP 4x
slot. Motherboards using ALi's M1631 (Aladdin TNT2) or Intel's
i810/810E chipsets do not support an AGP slot. All Socket 370
motherboards have PCI slots and the older types of Socket 370
motherboards have ISA slots. ISA slots are more common on
motherboards using non-Intel chipsets. Almost all Socket 370
motherboards are ATX (though a few AT Socket 370 motherboards
are known to exist). Only very few Tualatin motherboards
featured one or 2 ISA slots. Usually motherboards with the Intel
i815 chipset have no ISA slots, except when the motherboard is
equipped with a bridge chip. The bridge chip may cause some
problems when using ISA sound cards.
The Intel i810/815 chipsets also only support up to 512 MB of
memory. Its main competitors didn't have that limitation.
Today: Popular choices these days are either a 1000MHz
Coppermine or, if the motherboard supports it, a 1400MHz
Tualatin-s. Both these processors are about the fastest of their
kind and widely available. The 1400MHz Tualatin-s is about as
fast as a 1400MHz AMD Thunderbird while consuming about half the
power, which helps in keeping case temperatures down. A number
of BX Socket 370 motherboards were also made, just get the
fastest processor available for your board.
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