CPU Scaling Analysis, Part 2: Intel Pentium III Scaling and Upgrading – THG.RU

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The Pentium III: Already An Oldie?

It seems these days as if Intel would prefer phasing out the Pentium III immediately in favor of the Pentium 4. Intel is indeed increasing its efforts to make the Pentium 4 a worthy successor of the highly successful Pentium III. However, Intel’s new flagship CPU is having a rather hard time to beat AMD’s Athlon or the Pentium III, especially when operated at equal clock speed. Pentium 4’s other flaw is the fact that is has to be combined with RDRAM memory right now, which drives the system costs into the sky if you need more than 128 MB main memory. Lots of Pentium 4 CPUs are sold in bundle with RDRAM memory to make the package more attractive. Additional memory has to be obtained separately; brand types usually start at $ 200 per 128 MB RIMM.

Maybe you still remember the launch of Pentium Pro in 1995. At that time Pentium Pro was also unable to outperform a Pentium MMX.

Today, there are millions of Slot-1 and Socket 370 based systems in operation, working between 233 and 600 MHz on the average. A vast part of their owners do not want to replace the whole system and prefers a processor upgrade instead. In addition, SDRAM memory has become incredibly cheap, allowing most users to finally equip their machines with a decent amount of RAM. Why should anyone throw away a Pentium II system if he can most likely upgrade it with a faster CPU?

Pentium III: 3 Models

The first Pentium III (Katmai) is basically nothing more than a second generation Pentium II (Deschutes) with added streaming extensions (ISSE):

That’s the first Pentium III with Katmai core and 512 KB external L2 cache

It was soon followed by the second generation Pentium III, with the well-known ‘Coppermine’-core. Coppermine was first introduced for Slot-1 and was also the first Intel processor to reach 1 GHz, about 5 months after its release.

This one is the Slot-1 version of the current Pentium III with Coppermine core and 256 KB on-die cache, running at full core clock speed.

Only a few months after the introduction of the Slot1-Coppermine, Intel introduced the Pentium III for Socket 370 FC-PGA (Flip Chip Pin Grid Array), which is identical to the Slot-1 version in terms of features and the die. The move back from a slot-processor to a socket-processor was only logical, since the integrated L2-cache of Coppermine made the Slot1 CPU-PCBs obsolete. Intel used the slightly modifiied Socket370, which had already been known from the second generation of Celeron processors.

Today, the Pentium III has returned to the socket due to keep the costs down.

The Pentium III for FCPGA is the only version still available. The older packages have pretty much been phased out. It is available in various versions between 600 MHz and 1 GHz with either 100 or 133 MHz processor bus clock. The fastest type with 100 MHz FSB runs at 850 MHz core clock, while the fastest version with 133 MHz FSB runs at 1 GHz today.

Upgrade Mania

As already mentioned in the introduction, it is often possible to upgrade existing Pentium II and Pentium III systems with a faster processor. Slot-1 versions are hardly available anymore, leaving you a choice of just two Socket 370 processors, the Pentium III and the Celeron. Don’t worry if you should own a Slot-1 system. Adapter boards enable you to run Socket370 processors in Slot1 motherboards.

That is a Socket 370 to Slot-1 converter board.

The same, with the CPU installed this time.

Two types of converter boards are available.

Type one just converts the format (Slot-1 to Socket 370) and is only useful for the last generation of Slot1-motherboards. This type of converter sometimes comes with jumpers to adjust multiplier, FSB and core voltage. The settings are only passed to the motherboard and have no effect if the motherboard does not support them. The multiplier of Pentium III or Celeron processors is usually locked, making those jumpers pretty useless.

Type two comes with its own voltage regulator, supporting a much wider range of Slot1-motherboards, including the ones that don’t support Pentium III’s lower voltage requirements. Still the new CPU requires a BIOS which supports it.

Upgrade Mania, Continued

There are three important conditions you need to be aware of before purchasing a new processor:

Does my motherboard support the core voltage for the new processor?

Slot-1 or Socket 370 motherboards that are not older than a year will definitely be able to support all Pentium III or Celeron processors. Not all of those motherboards will support the 133 MHz front side bus (FSB or processor bus clock) though.

Depending on the chipset of the motherboard and its age, you will see the following situation:

Please note that the range of the voltage regulator is decided by the motherboard-maker! Some old boards may be able to supply 1.65 V, while others may not. The year given in the table is an estimate only and meant as an orientation for you. Please always check the features of your motherboard. It is also possible that certain motherboards supports even higher or lower voltages.

Upgrade Mania, Continued

Does the motherboard manufacturer offer a BIOS-update that supports my favorite CPU?

Check the company’s homepage or contact your local dealer. Companies usually keep updating their BIOS versions in order to make their products compatible with newer processors. BIOS support is important! Even if your motherboard is able to supply the right core voltage and FSB speed, the system will not run correctly without BIOS-support of the chosen processor.

Which Front Side Bus speeds are supported by my motherboard?

Check your manual for detailed information. Boards with Intel’s LX or ZX chipset only support 66 MHz. In that case, you will have to use a Celeron plus a Socket 370 to Slot-1 adapter board. The Celeron requires between 1.5 and 1.65 V core voltage. Please make sure that either the motherboard supports this or the adapter board comes with a fully featured voltage regulator. Any BX motherboard or VIA Apollo Pro supports 66 or 100 MHz (Celeron up to 800 or Pentium III up to 850 MHz). Intel 810E, 815, 820 and VIA Apollo Pro 133(A) support 133 MHz as well (Pentium III 1000 max). Please also check the table above and ask the manufacturer or local dealer.

Let’s summarize: The board needs to support the required voltage and Front Side Bus clock. Multipliers cannot be altered, so make sure you get the right processor version (100/133 MHz in the case of the Pentium III). Finally, you need to update your motherboard BIOS in order to support new generations of CPUs. If you cannot get an appropriate BIOS update, then you can only upgrade your CPU by using a faster version of the same processor model that you are currently using. In this case do not switch to another CPU type. Also do not forget to purchase a suitable CPU cooler and fan.

Don’t Forget The Graphics Card!

For this topic I would like to refer to one of my recent articles, which deals with the different GeForce 2 graphics chips from nVIDIA. The Scaling Analysis proves that, in case you want to improve your system’s 3D-performance, it is usually a better idea to get a mid-class processor plus a fast graphics card instead of upgrading to the fastest processor available. Even a fast Celeron offers good frame rates for nice gaming experiences once it is teamed up with a fast graphics card.

Test Setup

Sorry about the missing Pentium III 1 GHz – unfortunately I did not have this CPU when I ran the benchmarks. However, as you will see later, this is by no means crucial because ultimately the graphics card has a greater impact on 3D-performance than the processor.

SYSmark 2000: Windows 98 SE

The score in Sysmark2000 and thus the performance of current office applications improves with faster processors and faster hard drives. The graphics-card has today no influence on those results.

Mercedes Benz Truck Racing

The result is quite surprising: At 1024×768, the frame rates remain the same once a Pentium III runs at 733 MHz. Only the faster graphics card will enable higher frame rates.

Quake III Arena: 1024×768

At the resolution of 1024×768 there are only small differences between the various Pentium III types. nVIDIA’s GeForce 2 MX is definitely acting as the bottleneck, as the frame rates does not increase with faster CPU clock rates. GeForce 2 GTS and Ultra perform much better, but even with the GTS you can see its fill rate limitation when using the Pentium III 933. Between 733 and 866 MHz, the frame rate increased by 4 fps, but only by 2 fps between 866 and 933 MHz.

Quake III Arena: 1600×1200

At the top resolution of 1600×1200 a Pentium III 800 demonstrates quite sufficient performance. Greater CPU power has no effect on Quake III frame rates. Even the mighty GeForce 2 Ultra is limiting the theoretical frame rate.

SPECviewperf 6.1.2: Advanced Visualizer

The Visualizer is not able to get much out of high processor speeds. The real differences result from the use of those three graphics boards. The GeForce 2 Ultra is definitely a better investment than a Pentium III 933 plus any of the slower graphics cards.

SPECviewperf 6.1.2: Lightscape

Lightscape demands strong performance from both the CPU and the graphics card. Still a fast graphics card is more valuable than the fastest processor.

Conclusion

The Pentium III is not dead! I am not sure how long Intel will keep this processor alive, but right now it looks like we will still have the pleasure for many months.

If we forget former problems (i.e. the fiasco with the 1.13 GHz version and persistent delivery delays of Pentium III models last year) we should be aware of the fact that the P3 Coppermine is still an excellent chip. Like most other Intel CPUs, it is highly overclockable (only by raising the FSB speed) and capable of running in multi-processor environments. Besides that, the variety of available platforms is quite impressive: There are chipsets with integrated graphics, with SDRAM or DDR support, RAID, dual CPU motherboards etc.

More important is that millions of users around the world are already working with Pentium III systems and possibly intertested in an upgrade. Here’s a short list with my personal recommendations:

• RAM! At current SDRAM prices, 128 MB of additional memory is relatively inexpensive and will ensure that your system runs as fast as possible. Less access to the swap file and better system usability are just two of the direct benefits of an increase in RAM. Also, your system will be ready for Microsoft’s next generation operating and office systems.
• For which tasks do you normally use your computer? After studying the benchmark results (also see the Athlon scaling article) we should be happy that the product cycle for microprocessors is basically slowing down. There are only few applications available for home use which would require a processor at > 1 GHz. Having a system which runs at “only” 500 MHz might already sound shabby for some of you, but let me tell you that you won’t even notice an upgrade to e.g. 800 MHz if you are just using Word and MSIE.
• Gamers – do not overrate the benefits of a GHz processor! Every model at 500-700 MHz will perform well for some time, and those between 700 and 1000 MHz should last you for at least 12 months. Remember, the key to more 3D-performance is a faster graphics card! Stay tuned for our final GeForce 3 review as well!
• What about your hard drive? If you are using a model that is two years old or older, you might consider getting a new one, not only for larger capacity, but also for better performance. New hard drives are considerably faster than old ones. You will definitely feel the difference each time you boot Windows!