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Intel P4 Northwood CPU Review

The Pentium4 has changed once again, and this time the enthusiasts out there might just give a damn about it. Let's see how it stacks up against AMD's fastest 2000+ CPU.

Intel moved far away from the overclockers, hobbyists, enthusiasts—whatever you want to call them—when they embraced RAMBUS and the Pentium4. Times have changed. With the introduction of the Intel i845, the VIA P4X266, and the SiS645 chipsets, RDRAM is now a thing of the past. Even Intel officially signed off on the Pentium4/DDR combination with the introduction of their i845 chipset last month. From a tweaker's perspective, it was a tremendous move in the right direction, but it still wasn't enough.

Now phase two of a monumental shift has occurred, and this shift will give you a reason to stand up and notice of Intel once again. You may not be thinking about buying one of their CPUs right now, but that may change by early summer with some attractive Pentium4 pricing. Intel's own lowdown on their new 2GHz and 2.2 GHz Northwood CPUs is available here.

To get a better idea of where the P4 is going, we first have to see where it is now. The last major alteration the Pentium4 underwent was a change in its packaging. In fact, the P4 in its current S478 package has not been around all that long. We are, however, hoping it will stay around a while. The last link will give you information on the previous P4 core, code-named Willamette. We will be noting the major differences in this article, so enough of the fluff. . .what's new?

The Package:

 

As we mentioned, the packaging is fairly new and is composed of a 478-pin design with integrated heatspreader. One of the first things most folks notice about the heatspreader is that it has a hole in it, as you can clearly seen in the picture below.

The first question we usually get from everyone is, "Why is there a hole in my CPU?" The answer is that the hole is there to keep pressure from building up under the heatspreader when it is attached and cured by heated epoxy. The second question is usually the same from everyone as well. "What if I get something in it?" Well, with the obvious exception of heatsink paste, there should never be anything else on it besides possibly a cleaning fluid of some sort. As long as you keep fluids out of the hole and make sure your heatsink paste is non-conductive, you are going to be OK. We've tried our best to "fill one up" with paste, and it did no harm at all. No, no keychains yet. . .sorry.

The heatspreader is there to do exactly that, to spread heat from the CPU core to the heatsink. Intel has given us a larger mounting surface for our HSF units than the competition's, and that is certainly welcome. One of the offshoots of this is that they have created what is very nearly an indestructible CPU under normal handling conditions. If you crush the core of this CPU, like so many of us have done with our AMD CPUs, you are certainly doing something very, very, very wrong. Odds are if you accomplish that, you probably shouldn't be anywhere around electricity in the first place.

Along with the obvious outside changes in the Pentium4, there are three major changes that we cannot see on the inside.

The L2 Cache:

Intel has decided to increase the amount of on-die L2 cache to 512KB, up from 256KB on the previous Willamette core. Many of you will see the obvious advantage of this; it gives the CPU twice the storage room to work with before it must go out across the system bus to RAM to fetch needed data. In many cases, the extra 256KB is going to speed up processing time all on its own.

Copper Interconnects = Die Shrink = Less Power Needed:

The next big change for the P4 deals with the material used for the connections on the CPU die. Intel is now using copper interconnects for Northwood as opposed to the aluminum ones used by Willamette. Interconnects are the tiny "wires" that are used on the die, and this change in material has allowed for a die shrink. Instead of a 0.18-micron structure, Intel is now using a 0.13-micron structure that connects 55 million transistors. This change has allowed for the increase in L2 cache by making more room available on the P4's die without making the physical dimensions so large that the wafer cost would rise above an unacceptable level. The smaller copper interconnects have not only allowed a die size shrink of an overall 30% (down to 146mm²), but it also allows the Pentium4 to consume less power doing its job. A voltage drop from 1.7v to 1.475v may not sound like a lot, but it's fairly sizeable when thought of as a percentage of around 15%.

Less Heat:

With the die shrink and voltage drop, there comes less heat. Intel has their official numbers, but they always seem a bit inflated to us. They call their specifications on heat "TDP" or "Thermal Design Power", and they are the numbers OEMs use to design their cooling systems with. Whereas the 2GHz Willamette was rated at 72 watts, the 2.2GHz Northwood spec calls for a heat dissipation of 55 watts, with the 2GHz Northwood coming in at 49 watts. If anything, we know that it feels cooler to the touch when at load.

Core Speeds and Package Stability:

All of this adds up to a CPU that we will very likely see one day approaching the 3.5GHz mark—if not up to 4GHz and beyond. That's what rumor has to say, so take that information with a grain of salt. Something we do know, though, is that the socket 423 version of the Pentium4 was a bastard child as soon as it left the gate, because everyone knew the package was doomed. The S423 package was already known to be on the chopping block with the S478 replacement not far behind. For many of us that upgrade on a regular basis, this was just one more strike against the Intel P4 CPU. The word is that the S478 is here to stay for a good while, and that news is very welcomed. We will be seeing Intel's new "Granite Bay" chipset later this year, which will include dual DDR memory channels, and our S478 CPUs will still work just fine with it.

Still, when we saw our Northwood samples arrive, we did have a few questions. For one, our CPU was delivered to us direct from Intel in a socket 479 BGA socket!

Hey! Somebody stole one of my pins! Or did someone just slip me an extra hole? Seriously, the S479 did make us ask a couple of questions, and here is what Intel had to say:

"As far as the 479 pin pin protector, there is no 479 product planned. Just some old sockets the factory had lying around."

So don't be alarmed and have no fear, our S478 CPUs should do us proud for quite a while.

Pricing:

We don't usually talk a lot about pricing, but cost has certainly played a large part in our buying decisions lately with CPUs. As of this morning, a 2.2GHz Northwood will cost you around US$562 in quantities of 1000 with the 2.0GHz Northwood ("2.0A" signifies a Northwood CPU, as opposed to a Willamette in the same package) running you about US$364 in quantities of 1000. Even at launch, we're seeing CPUs for sale in the US$425 range, and that will surely be falling as gray market CPUs start coming back into the states from overseas. Come summertime, we will be looking at some very cheap 2.0A CPUs.