RADIFIED
Guide to the
Intel Northwood Pentium 4 CPU

Posted:
22oct2001

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My little blue friends from planet Intel will explain everything & bring you up to speed on the Northwood Pentium 4 CPU.

Intel Northwood Pentium 4 CPUIntel Northwood Pentium 4 CPUIntel Northwood Pentium 4 CPUIntel Northwood Pentium 4 CPU

The latest Pentium 4 CPU from Intel, code-named Northwood, (affectionately referred to as 'Northie') was officially released 07jan2002. Its most significant design improvements are:

  • Core die shrunk to 0.13-micron [from 0.18 micron]
  • L2 cache increased to 512KB [from 256KB]
  • Transistor count increased to 55 million [from 42 million]
  • Default voltage lowered to 1.5v [from 1.75v]

The Northwood P4 comes with socket-478 packaging (478 pins), also referred to as mPGA478. It looks like this:

Intel Northwood P4 socket-478 packaging

Updated:
25jan2003

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A larger image of the Intel Northwood P4 CPU is posted here (760x624, 28KB). Notice how the chip itself is well protected beneath the hard shell casing, making is nearly impossible to damage. The casing design makes heatsink installations a snap.

Update 10feb2004 - Before we go much further, you should know that the Northwood has been superceded by Intel's next-generation Pentium 4 CPU: the Prescott. For info about this new chip see here:> Intel Prescott Pentium 4 CPU. Now we'll get back to the Northwood.

Note that you used to be able to purchase two different socket-478 P4's today. But one of them was not a Northwood. The Northwood Pentium 4 is based on the new .13-micron die Tualatin core (smaller, 146mm² in size), with copper interconnects (which are tiny wires or 'traces' that connect transistors).

By contrast, older P4s were based on the 0.18-micron Williamette core (larger, 217mm²), with aluminum interconnects. See here for an image (61KB) that illustrates the difference in size between the old & new P4 CPUs.

The Northwood's smaller transistors are able to switch faster and generate less heat than previous, hotter-running P4s. This allows the Northwood P4 to reach higher clock-rates than its larger, Williamette-based P4 cousin. Note Chris' comments from his Northwood review at GamePC:

Northwood runs extremely cool, considering its massive clock speeds. With the retail Pentium 4 cooler, at a default clock speed of 2000 MHz, the Northwood maxed out a temperature of 89.5°F. In comparison, our Willamette P4 ran well over 100°F.

Northwood P4s overclock well, especially with their lower (1.5v default) voltage. Lower voltage means reduced power consumption and less heat generated, which translates into improved stability.

The Williamette-based 2GHz P4 is rated at 75.3 watts. Far as I know, this is the highest-rated TDP (Thermal Design Power) of any CPU. The 2GHz Northwood P4 is rated at 52.4 watts (see here). The 2.2GHz Northwood is rated at 55.1 watts. [You know that a 60-watt light bulb burns cooler than a 100-watt bulb.]

Preliminary reviews indicate that a 2.0GHz Northwood P4 has a good chance of reaching (being overclocked to) 2.5GHz, which corresponds to an increase of 25% over the default clockrate. The 1.6GHz denomination is virtually assured to reach 2.1GHz.

In terms of overclockability, this makes the Northwood P4 (especially the 1.6A) another Celeron 300a. The C300a was a legendary Intel CPU of yore, known for its ease of stable overclocking, rendering $500 performance for ~$125. People are already referring to the 1.6A (~$138) at the new Dancing Queen, cuz it does the dance (overclocks) so reliably to speeds averaging 2.3GHz. Note Chris' comment regarding overclocking a 2.0GHz Northwood P4 (3rd paragraph):

"When we say stable, we mean it too. We were able to run through a set of benchmarks at 2.5 GHz without a single crash. In fact, our testbed is still running right now at 2.5 GHz. That's a 25% overclock without any external modification to the chip or motherboard!"

The first Intel Northwood Pentium 4 CPUs have been released in 2.0 and 2.2 GHz flavors. Rumor has it that Intel will also (later) release a 1.6 and 1.8GHz Northwood. It's looks like they're already available.

Intel is differentiating the Northwood P4 from the it's older Williamette cousin by adding the letter 'A'. Where the P4 is concerned, that little 'A' means A_lot. If you order a 2.2GHz P4 CPU, you're assured that it's a Northwood, cuz there are no Williamette-based 2.2GHz P4s.

Intel P4 CPU's that end with the letter 'A' are designed to run at 400-MHz system bus. CPU's that end with the letter 'B' are designed to run at 533-MHz. And newer CPU's that end with the letter 'C' run at 800-MHz system bus.


Intel is sneaky about the way they name their CPUs. The most obvious name changes rarely correspond to the most meaningful design changes. Rather, the most desirable design improvements (e.g. die size reductions) are often obscured by subtle name changes (like adding the letter 'a', for example).

This means that you must do your homework if you want to select the CPU that represents the best combination of performance, stability, longevity & value. Gone are the days when buying the latest processor was a safe bet.

For example, most people don't know that you can't directly compare clock-cycles (MHz) of the Pentium 3 with those of the Pentium 4. A 2GHz P4 does *not* process twice the number of instructions of a 1GHz Pentium 3. If you think that Intel will ensure you know this, you're mistaken.


Key features of the Intel Northwood Pentium 4 CPU in a nutshell:

  • 0.13-micron die Tualatin core [old P4 = .18-micron Williamette]
  • 146mm² core size with copper interconnects [old P4 = 217mm² with aluminum interconnects]

  • 512KB L2 cache [old P4 = 256KB]
  • socket-478 (pin) packaging [old P4 = both socket-423 & -478 packaging]

  • 1.5v default core voltage [old P4 = 1.70v and 1.75v]
  • Contains 55 million transistors [old P4 = 42 million]

  • 8KB super-fast L1 cache [old P4 = same, P3 has 16KB, but not the super-fast stuff]
  • 64-bit quad-pumped 100MHz FSB (effective 400MHz) [old P4 = same]

  • 2 double-pumped ALUs (Arithmetic Logic Units) do the work of four, running at twice the processor core speed [old P4 = 2 single-pumped ALUs]
  • No support for dual-processor system configurations

  • DDR-SDRAM chipset support scheduled for Q1 2002 [old P4 = same]
  • uses Rambus DRAM [old P4 = same]

  • 144 new SSE2 instructions [old P4 = SSE2, but not these 144 new ones]
  • 20-stage pipeline [old P4 = same, P3 = 10-stage]

  • uses NetBurst technology instructions [old P4 = same]
  • new ATX 2.03 spec for mounting heatsink retention fittings [same]

  • requires additional 12-volt 2x2 power supply connector [same]

You can purchase power supplies designed specifically for Pentium 4 systems. I asked the folks at PC Power & Cooling, "What's different about Pentium4 power supplies?" You can read their response, which is posted here. Intel discusses P4 power supply requirements here.

Word on the street is that not all socket-478 motherboards will require a new case or power supply unit (PSU). Some reviews claim that Asus includes an adapter kit so that you won't have to buy a new case or PSU, for system upgrades.

Most people who have already built P4-based systems claim that you don't need a new case, but that you should get an ATX 2.03-compliant P4-approved PSU. Enermax also makes a nice 470-watt P4-compatible power supply you can buy for $99 [EG475P-VE-SFMA].

Pentium 4 motherboards are larger than P3 boards, so make sure your case is big enough to accept the larger P4 boards.


I have a friend with a P4 system (a home system, not a stripped-down benchmarking rig). He claims that it's "rock solid". When I heard the way Joshua said the words rock solid (including unprintable, colorful adjectives), I knew that the Northwood would be my next CPU. Another review posted here echoes Joshua's sentiments.

Perhaps I should note that I'm not necessarily an Intel fan. Rather I'm a stability fan. And Intel chipsets rule the stability world. I'd gladly pay extra for a stable system (within reason, or course). My current system (Intel-based) is rock solid, even tho it's overclocked.

Kyle at [H]ard|OCP seems to agree by saying (next-to-last paragraph):

Intel components still are the pinnacle when it comes to building a problem-free system that we can rely on.

Chris at GamePC seems to concur (first paragraph):

Our particular market, the high-end / gamer segment, seems fairly split, many loving the raw speed and low price of the Athlon, while others love the well-endowed memory bandwidth and ultra-stability of the Pentium 4 platform.

To be clear, I seek maximum stability, with maximum performance at a minimum price. In that order. Speaking of minimum price ...