Custom PC - UK (2021-05)

L

ike that Simpsons episode where the director’s

commentary for The Postman is just Kevin

Costner repeatedly apologising into his

microphone, there needs to be a monument to the Pentium

4 somewhere at Intel’s HQ to remind people how badly you

can get it wrong. You might think Intel is behind the

competition now, being stuck on a 14nm node and a lack of

cores compared with AMD, but at least Comet Lake is a half-

decent microarchitecture. You’d struggle to say the same for

the Pentium 4.

Let’s put the Pentium 4 in its historical context. Intel came

up with the Pentium brand to distinguish its processors from

the competition in the post-486 era, and it had worked.

People looked for the Pentium brand as a seal of quality, and

that had largely continued throughout the Pentium II era.

Then, soon after the launch of the Pentium III, AMD brought

out its first premium CPU brand, the Athlon.

There were teething problems with Athlon, as you might

expect, but it showed that AMD could beat Intel in terms

of performance. Not only that but, to Intel’s shame, AMD’s

Athlon later beat the Pentium III to the 1GHz finish line at the

end of 1999.

FIRST MISSTEPS

There were some clues to what was to come with Pentium

4 in the latter days of the mainstream Pentium III, when Intel

introduced a 133MHz front side bus (FSB). Now, the 133MHz

FSB was a great idea, as it not only bumped up the CPU

speed, but also the I/O speed between the CPU and the

Huge clock speeds, hot running and rubbish

performance. Ben Hardwidge looks back to the time

when Intel got it catastrophically wrong

motherboard chipset’s Northbridge – if you used 133MHz

memory with it, you got a load more bandwidth.

The problem was that Intel’ s two chipsets for it were

both flawed in crucial ways. At the top end was 820, with

pricey motherboards and the need for a new type of

memory made by Rambus called Rambus Dynamic RAM

(RDRAM). While SDRAM was generally running at up to

133MHz, RDRAM could run at 400MHz. Not only that, but

by transferring data on the rise and fall of the clock, much

like DDR memory today, it effectively ran at 800MHz.

It wasn’t quite that simple though. At this time, RDRAM

had a 16-bit bus, compared with the 64-bit bus used for

SDRAM, and it also had much higher latency. RDRAM still

had higher bandwidth by the end of it, but it wasn’t quite

the trouncing people expected. Also, all that bandwidth

didn’t make a massive difference when the front side bus

Retro tech

INTEL PENTIUM 4

An Intel Pentium 4

in its dinky Socket

478 packaging

It would leave existing CPUs

looking like relics. At least,

that was the idea

RETRO TECH / ANALYSIS

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