Recently I gutted a few old PC’s. The physical difference between the Pentium 3 (P3) from 1999 and Pentium 4 (P4) from 2005 were stark. It made me think of the way computers have progressed in terms of performance and power usage.

Pentium 3

The Pentium 3 that I removed uses a Slot 1 connector. basically it sits on a board that gets inserted into a slot on the motherboard. The little daughter board reveals a bunch of support hardware once the black cover is removed. There are a couple of chips that look like they might be for the RAM Cache. Looking this up in Wikipedia confirms this thought, “The L2 cache is off-die and runs at 50% CPU speed.” It also states a TDP of 28W. No wonder it can get away with a small fan and heatsink.

https://en.wikipedia.org/wiki/List_of_Intel_Pentium_III_microprocessors#.22Katmai.22_.28250_nm.29

Pentium 4

On the other hand the P4 HT 630 is a LGA 775 type of socket, a bunch of balls on the bottom that make contact to the socket on the motherboard, 475 of them! This socket design was one of the last for the P4. The P4 is a Prescott 2M and has a TDP of 84W. Hence the big fan and heat sink.

https://en.wikipedia.org/wiki/List_of_Intel_Pentium_4_microprocessors

In contrast, a few years ahead in 2009, a more modern computer, with more processing power would have a processor that uses about 40-50W TDP. So heat-sinks and fans have gotten smaller. Along with the power supplies, I had a Dual Xeon Circa 2004 that had a 1000W power supply, it was fast for it’s time, but also a space heater when it was running hard.

Simple Benchmarks

Running a Pi Benchmark written in C, out to 256000 digits. Lower is better.

1999: Old P3 at 700 MHz Time: 13026 seconds TDP about 28W

2004: P4 at 2400 MHz Time: 3741 seconds TDP 84W

2009: Intel(R) Celeron(R) M CPU 520 @ 1.60GHz Time: 2747 seconds TDP 30W

2011: Intel(R) Core(TM) i3-2100 CPU @ 3.10GHz  Time: 986 seconds TDP 65W