Ye Olde Rad Blog

The boyz at Intel have released their next-generation CPU for desktop computers, code-named Prescott. If you want to read all the geek-speek, a Google search pre-configured for the terms Intel Prescott is posted here. But most folks simply want to to know the answer to two questions:

Do I want one? and How much will they cost? The answer to the first is: not yet. Right now, Prescotts run a little slower than a similarly clocked Northwood (due to a longer, 31-stage pipeline). Prescotts will sell for the same price as their Northwood cousins at identical speed-points.

You will recognize PrEscotts by the addition of the letter 'E' to the CPU name, such as P4-3.2E. I looked at Newegg and you can find them there already, but only at the lowest 2.8-GHz speed. The rest of the speeds are scheduled to ship next quarter. Note that this is NOT the same as the 'EE' outrageously expensive Extreme Edition CPU, based on the Northwood. You might also try Atacom.

This is Intel's first major CPU re-design since the release of the Northwood CPU some two years ago on January 7th, 2002. Note that the current Northwood P4 max'es out at 3.4-GHz. The Prescott will initially release at the following (GHz) speed-points: 2.8, 3.0, 3.2, & 3.4.

Note that these new Prescotts are rated no higher than current Northwood CPUs. In the third quarter we will see speeds of 3.8 & 4.0-GHz. This would be the time to get a Prescott, since they need the higher clock-rates to make the longer pipeline worthwhile. All Prescotts run at 800-MHz FSB (only).

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The casual observer will notice no major changes, since the current Northwood and new Prescott will both wear the same Pentium 4 name tag. The most significant change is the reduced manufacturing process down to 90-nm (nano-meter, or 0.09-micron) from the current 130-nm (0.13-micron) used by today's Northwood.

The smaller manufacturing process results in a corresponding die-size reduction (smaller chip). Precott is 112-mm², while the Northwood is 131-mm². Usually, smaller chips produce less heat, but the Prescott seems to buck this trend, which is bad news. Thermal power on the 3.4-GHz Prescott actually *increases* to 103-watts (from 89-wats for the Northwood of the same speed). That is one hot chip! Think of the heat produced by a 100-watt lightbulb, which can burn your hand.

The second-biggest change will be a doubling of the L2 cache to 1-MB (from Northwood's 512-KB). The L1 cache is also doubled to 16-KB, from Northwood's 8-KB. The larger L1 cache has a higher access latency (bad). It's like a bigger, slower truck. Will the bigger, slower truck allow you to move your household effects more quickly? The answer is: it depends (on what you're moving). It will likely be faster if it allows you to make one trip instead of two.

Prescott comes with SSE3 (containing 13 new instructions), altho I don't know of any programs that use these new instructions yet.

It also comes with a longer, 31-stage pipeline (nick-named the "Baskin Robbins" pipeline) The pipeline is analogous to the length of a car assembly line. By contrast, the Northwood has a 20-stage pipeline. A longer assembly line would take longer to produce each car, unless you can speed it up .. which is what Intel plans to do with Prescott (by increasing the clockrate, eventually to 5-GHz).

Had enough information overload already? Two final key statistics:

The new Prescott comes with a whopping 125-million transitors (which is good, the Northwood has 'only' 55-million) and the Prescott uses a slightly lower default voltage: 1.385-volts (Northwood = 1.5-volts). My advice: buy a Northwood until Prescotts exceed Northwood speeds. Let others (called "early adopters") work out the kinks for you. When actual users report the coast is clear, it will be time to jump in with both feet.

If you currently have a motherboard with either the Intel 865 or 875 chipset, you should be able to run a Prescott with a simple BIOS flash-update, since they use the same 478-pin configuration as current Northwood P4s. Changes incorporated in the Prescott should allow Intel to reach the 5-GHz mark by next year. If you're interested in Prescott overclocking, see here and here. Personally, I'm concerned by the fact that Prescotts run hotter than Northwoods. Heat is a CPU's worst enemy and is always bad for stability.

The succesor to the Prescott will be code-named "Tejas" (pronounced "teh'-hass"), scheduled for release somewhere around January, 2005. Other rumors claim Intel may've scrapped the Tejas project.