RETRO TECH / ANALYSIS
package. The answer was to manufacture the CPU package
on a usual square format without the L2 cache, and to then
mount that package on a circuitboard that contained the cache,
resulting in the Pentium II in 1997. It had 7.5 million transistors,
produced on a 350nm manufacturing process.
Like the Pentium Pro, the CPU used a separate ‘back-side bus’
to communicate with the cache, but unlike the Pentium Pro, the
Pentium II could only run the L2 cache at half the speed of the
CPU. Intel attempted to counter the performance of the cache
by first doubling the amount of L1 cache, from the Pentium
Pro’s 16KB to 32KB on the Pentium II. The Pentium II’s L2 cache
also had a 16-way associativity, compared with 8-way on the
Pentium Pro. A higher associativity means the CPU has a greater
chance of finding the data it needs in that cache, but that it can
take longer to search for it than a cache with lower associativity.
The other way Intel bumped up the Pentium II’s
performance was by simply equipping it with a lot of this L2
cache. All the first models of Pentium II came with a pair oflarge 256KB cache chips, giving you 512KB in total – more than
you found on some Pentium Pro CPUs.
By the end of it, you had a circuitboard containing a full CPU
package in the middle, with two large cache chips next to it.
This was then encased in a box with a thermally conductive
metal back. The whole package was called a single edged
contact cartridge, or SECC, and you would then attach a
heatsink and fan arrangement to the metal back, and slot the
whole setup into your motherboard.
The SECC package looked good on the surface, but if you
took one apart, you could see that it was a bit of a bodge job. I
was working in a computer shop at the time, and we joked that
the Pentium II was a ‘Socket 7 on a circuitboard’ – you could
even see the solder points where the socket pins could have
been located on the CPU package. It was still a normal square
CPU package – it was just mounted on a board instead.
Performance was mixed. If you were running full 32-bit
software in Windows 95, then the Pentium II was generally
faster than the Pentium MMX, but the latter still had the edge
in some 16-bit software, such as MS-DOS games. It also didn’t
help that the first Pentium II CPUs used the same 66MHz
front side bus as the final Pentium MMX chips, with the first
Pentium IIs running at 233MHz, 266MHz and 300MHz, and a
333MHz variant arriving later, following a die shrink to 250nm.
This meant that, in some cases, the top-end 233MHz Pentium
MMX was faster than the low-end 233MHz Pentium II.Think outside the box
The processor’s new clothes came well and truly off in 1998
when Intel introduced its budget range of Slot 1 CPUs, with
the still ridiculous name of Celeron. The first generation of
Celeron CPUs, codenamed Covington, removed all of the L2
cache from the circuitboard, as well as all the fancy, hologram-
clad packaging. This left you with a peculiar-looking green
circuitboard with a square CPU clearly soldered into the middle
of it - Intel called this non-cartridge arrangement a SEPP format.
The lack of cache meant these Celerons performed poorly
at the time, pushing people looking for a budget CPU towards
AMD’s K6 line-up, which still used the aging Socket 7 formInside a Pentium
II die – that’s 7.5
million transistors
produced
on a 350nm
manufacturing
process, and with no
integrated L2 cacheSlot 1 Celerons didn’t
come in a fancy
chassis, and the first
models didn’t come
with any L2 cache
either. Photo by
QurrenRETRO TECH / ANALYSIS
package. The answer was to manufacture the CPU package
on a usual square format without the L2 cache, and to then
mount that package on a circuitboard that contained the cache,
resulting in the Pentium II in 1997. It had 7.5 million transistors,
produced on a 350nm manufacturing process.
Like the Pentium Pro, the CPU used a separate ‘back-side bus’
to communicate with the cache, but unlike the Pentium Pro, the
Pentium II could only run the L2 cache at half the speed of the
CPU. Intel attempted to counter the performance of the cache
by first doubling the amount of L1 cache, from the Pentium
Pro’s 16KB to 32KB on the Pentium II. The Pentium II’s L2 cache
also had a 16-way associativity, compared with 8-way on the
Pentium Pro. A higher associativity means the CPU has a greater
chance of finding the data it needs in that cache, but that it can
take longer to search for it than a cache with lower associativity.
The other way Intel bumped up the Pentium II’s
performance was by simply equipping it with a lot of this L2
cache. All the first models of Pentium II came with a pair oflarge 256KB cache chips, giving you 512KB in total – more than
you found on some Pentium Pro CPUs.
By the end of it, you had a circuitboard containing a full CPU
package in the middle, with two large cache chips next to it.
This was then encased in a box with a thermally conductive
metal back. The whole package was called a single edged
contact cartridge, or SECC, and you would then attach a
heatsink and fan arrangement to the metal back, and slot the
whole setup into your motherboard.
The SECC package looked good on the surface, but if you
took one apart, you could see that it was a bit of a bodge job. I
was working in a computer shop at the time, and we joked that
the Pentium II was a ‘Socket 7 on a circuitboard’ – you could
even see the solder points where the socket pins could have
been located on the CPU package. It was still a normal square
CPU package – it was just mounted on a board instead.
Performance was mixed. If you were running full 32-bit
software in Windows 95, then the Pentium II was generally
faster than the Pentium MMX, but the latter still had the edge
in some 16-bit software, such as MS-DOS games. It also didn’t
help that the first Pentium II CPUs used the same 66MHz
front side bus as the final Pentium MMX chips, with the first
Pentium IIs running at 233MHz, 266MHz and 300MHz, and a
333MHz variant arriving later, following a die shrink to 250nm.
This meant that, in some cases, the top-end 233MHz Pentium
MMX was faster than the low-end 233MHz Pentium II.Think outside the box
The processor’s new clothes came well and truly off in 1998
when Intel introduced its budget range of Slot 1 CPUs, with
the still ridiculous name of Celeron. The first generation of
Celeron CPUs, codenamed Covington, removed all of the L2
cache from the circuitboard, as well as all the fancy, hologram-
clad packaging. This left you with a peculiar-looking green
circuitboard with a square CPU clearly soldered into the middle
of it - Intel called this non-cartridge arrangement a SEPP format.
The lack of cache meant these Celerons performed poorly
at the time, pushing people looking for a budget CPU towards
AMD’s K6 line-up, which still used the aging Socket 7 formInside a Pentium
II die – that’s 7.5
million transistors
produced
on a 350nm
manufacturing
process, and with no
integrated L2 cache
Slot 1 Celerons didn’t
come in a fancy
chassis, and the first
models didn’t come
with any L2 cache
either. Photo by
Qurren