Understanding the Pentium 4 line of processors
Written: Jan 16 '03
|
Product Rating:
|
|
|
Pros: Fastest processors in the PC marketplace
Cons: Different models can be confusing for the uniformed.
The Bottom Line: Good processor, good price. If you get the 1.8GHz Northwood, read my upcoming articles on motherboards and overclocking so you can run your machine at 2.4GHz or faster.
|
|
|
| stevelarrison's Full Review: Intel Pentium® 4, 1.8 GHz (BX80532PC1800D) Pr... |
With the ongoing tech-implosion, companies with deep pockets are positioned to outlast less financially secure competition. It has happened in all areas of technology, and the PC microprocessor marketplace is no different. After years of trying, AMD was able to put out a product that not only was had a competitive price with it's Athlon and Duron processors, but it also created a product that performed as well, or better than Intels' then-top-of-the-line Pentium III product line. While initially panned by the performance hardware community, the Pentium 4 has proved to be a product that is better than the best AMD can produce.
However, as you will discover by reading this review, the Pentium 4 has followed quite an evolutionary path. There are differences in form factor, amount of L2 cache, bus speed, and the existance of a new technology called Hyperthreading that must be taken into consideration when buying a new system, or when upgrading an older system. In addition to considerations about the processor itself, knowledge of the motherboard chipset is an important consideration in overall system performance.
This review will not be an attempt to discuss issues like benchmarking against AMD platforms, or to discuss the overclockability of Pentium 4 platforms. Instead, I will concentrate on the basics of the Pentium 4 architecture so that the buyer will be able to make informed purchases.
Generation Gap
Generation Gap in this case refers to a gap in overall processor performance. There are two generations of Pentium 4 processors. They are known as "Willamette" and "Northwood". The original processors were the Willamette generation. The fastest Willamette processor was the 2.0Ghz Pentium 4. If a processor is faster than 2GHz, it is a Northwood. However, there are also 1.6 and 1.8 GHz Pentium 4's that are Northwood generation.
The first question that you may want to ask yourself is "what difference does it make?" The question is very valid. The change from the Willamette to the Northwood generation processors involved several things. Most notable were a die-shrink from a .18 micron process to a .13 micron process. In addition to the die-shrink, Intel increased the amount of L2 cache from 256k to 512k when they changed processes.
What that means to you is quite simple. The die shrink means that your processor will run cooler. While this is most important to overclockers (people who "tweak" hardware to run faster than spec speed), it is really something that is good for everyone. Heat kills electronic components. By lowering processor temperature, temperatures inside your computer case are lower. This helps lead to longer lifetimes for all the components in your system. The increase in L2 cache has an even larger benefit for all users. While the exact increase in performance will vary based on the use of the computer, in general, you can expect about a Northwood generation Pentium 4 1.8GHz processor to be about 10% faster than a Willamette generation Pentium 4 1.8GHz processor. If you are buying a processor, the box will be marked as 256k or 512k of cache. Only get the 512k models. You will be glad. If buying a complete system, it may not be as clear. Either ask the vendor selling you about the processor, or use a program like WCPUID (available at www.h-oda.com) to tell you more about the processor.
Form Factor
One of the first things to look at in a Pentium 4 processor purchase is the form factor. When originally released, the Pentium 4 used what was called a "socket 423" architecture. Current Pentium 4 processors use "socket 478" architecture. The numbers 423 and 478 refer to the number of pins on the processor.
All Northwood generation processors (non-Xeons) use socket 478.
A Willamette generation processor can be either socket 423 or socket 478.
If you aren't sure if a processor that is 2.0GHz or slower is a Willamette or a Northwood, look at the amount of L2 cache. If a processor is faster than 2.0GHz, it is a Northwood generation processor.
If you have an older socket 423 system, there are convertors that will allow you to run a newer socket 478 processor in your old system. Currently priced at around $50, you can get convertors from places like PowerLeap. ( www.powerleap.com - look at the PL-P4/N ) Obviously you wouldn't want to get a socket 423 system new, but if you are looking at prolonging the life of an old system, it is worth looking into.
Bus speed
Pentium 4 processors use something that Intel calls "quad-pumped" architecture. Essentially, this allows the processor to simulate having a bus speed that is 4 times faster than the true bus speed. If you study the Pentium 4 architecture, you will find that faster bus speeds have a large effect on overall system performance.
Currently, Intel sells Pentium 4's that use a 100MHz Front Side Bus quad-pumped to be 400Mhz effective speed. They also offer a 133MHz Front Side Bus quad-pumped to an effective 533MHz speed. In late March, they will be introducing a 200Mhz Front Side Bus quad pumped to an effective 800Mhz speed.
A review of some of the older articles I have written on processors will show that a processor speed is based on bus speed times clock multiplier. In other words, a 2.4GHz Pentium 4 can be obtained by using a 24x clock multiplier and a 100/400 Front Side Bus. It can also be obtained by using a 18x clock multiplier and a 133MHz Front Side Bus. (Soon, a 12x clock multiplier and a 200Mhz Front Side Bus will be another way to acheive 2.4GHz)
As I stated earlier, Front Side Bus speed is very important to overall processor performance. Pentium 4 performance is more dependant upon Front Side Bus speed than any prior generation of processor. Although it will vary with individual benchmarks, you would expect a 2.4GHz Pentium 4 running a 133/533 Front Side Bus to be about 8% faster than a 2.4GHz Pentium 4 running a 100/400 Front Side Bus.
Hyperthreading
Hyperthreading is the name of a newer technology that is currently only available on the 3.06GHz Pentium 4. (Xeon and Itanium processors also have the technology) The first question most people ask is "What is hyperthreading?"
The answer is really quite simple, and also kind of cool. Multiprocessing operating systems allow applications to get processor time through constructs called "threads".
Until the introduction of the 3.06GHz Pentium 4, all PC processors were only capable of having the processor handle one thread at a time. Multiprocessing is made capable by having the processor switch threads that it allocates processing power to.
While working on any given thread, portions of the circuitry of the processor are idle.
Hyperthreading uses logic to simulate a multi processor system. Essentially, a hyperthreaded processor looks like 2 separate processors to the operating system. (Note: This only works with Operating Systems that allow SMP. In the Microsoft world, the only choices are Windows 2000, or Windows XP Pro. Users of Windows 9x, Windows ME, or Windows XP Home edition will not gain any benefits from hyperthreading. Linux users are all set.)
The next question someone is likely to ask about Hyperthreading is what the impact on performance will be.
That question isn't as easy to answer. In all honesty, each situation is unique. People who multi-task and use very resource intensive applications will benefit the most. But even if you don't knowingly multi-task, the nature of modern operating systems means that you really do multi-task.
Although Intel marketing hype will suggest that you will gain up to a 900% increase in performance while multi-tasking, the informed buyer will realize this for the marketing hype it is and not expect such a dramatic difference in performance. Though benefits vary widely, it isn't a bad rule of thumb to expect about a 20% increase in performance from hyperthreading.
Conclusion
Hopefully this article as been informative. In the near future, I will follow on with an article concerning another very important factor in system performance - motherboard selection. Please feel free to leave me comments on this article, or to ask questions about anything I may not have explained in enough detail.
Recommended:
Yes
|
|
|
|
Epinions.com ID:
stevelarrison
|
 - Top 500 |
|
Member: Steve Larrison
Location: Scottsdale, Az. USA
Reviews written: 171
Trusted by: 198 members
About Me:
Beer, the answer to, and the cause of all life's problems.
|
|
|
- Add to My Yahoo!: 
- Add to Google Homepage: 
© 1999-2009 Shopping.com, Inc.