Intel's Pentium 4 E: Prescott Arrives with Luggage

The Pentium 4 has come a long way since its introduction in the Fall of 2000. It went from being a laughable performer, to a CPU embraced by the community. Today Intel is extending the Pentium 4 family with the third major revision of the chip – codenamed Prescott.

Back when Prescott was nothing more than a curious block on Intel’s roadmap, we assumed that history would repeat itself: Intel would move to a smaller, 90nm process, double the cache and increase clock speeds. Intel has always historically behaved this way, they did so with the Pentium III and its iterations, and they did so with the first revisions of the Pentium 4. What we got with Prescott was much more than we bargained for.

Intel did move to a 90nm process, but at the same time didn’t produce a vastly cooler chip. Intel did double the cache, but also increased access latencies – a side effect we did not have with Northwood. Intel also moved to Prescott in order to increase clock speeds, however none of those speeds are available at launch (we’re still no faster than Northwood at 3.2GHz) and Intel did so at the expense of lengthening the pipeline; the Prescott’s basic Integer pipeline is now 31 stages long, up from the already lengthy 20 stages of Northwood. With Prescott, many more changes were made under the hood, including new instructions, some technology borrowed from the Pentium M and a number of algorithmic changes that affect how the CPU works internally.

If you thought that Prescott was just going to be smaller, faster, better – well, you were wrong. But at the same time, if you view it as longer, slower, worse – you’re not exactly on target either. Intel has deposited a nice mixed bag of technology on our doorsteps today, and it’s going to take a lot to figure out which side is up.

Let’s get to it.