CPU Scaling Analysis, Part 1: AMD Athlon – THG.RU

Introduction

Ever since the current Athlon processor based on the Thunderbird core was released, it has been very successful. AMD opened the market by keeping CPU prices significantly below the prices of comparable Pentium III models. With the new Pentium 4 being slower than the Athlon in the majority of benchmarks (even though Intel’s latest chip runs at clock speeds of up to 1.5 GHz), there is only Intel’s good-old Pentium III left as an alternative that could be used in affordable systems.

Besides its high price, Intel’s Pentium 4 faces the handicap that it can only be teamed up with Rambus DRAM (RDRAM). Therefore the user has to pay two premiums for a P4-platform in order to obtain high clock speeds (400 MHz RDRAM and 1.5 GHz P4) although it might not even necessarily pay off in terms of performance.

Of course the Pentium III is an alternative, as there are several platforms available, supporting SDRAM or DDR memory. Many people already worry about the future of Socket 370, as the succeeding Pentium 4 is not pin-compatible. If that is an issue to you, you should also keep in mind that Pentium 4’s Socket 423 is meant to be replaced by Socket478 and a new type of Pentium 4, code named ‘Northwood’ in September 2001.

This leaves AMD’s Athlon. The SocketA motherboard market has grown to offer a large variety, as there are many different models available featuring similar highlights to their Pentium III cousins. Main chipset supplier is the Taiwanese company VIA. Their KT133A is frequently used and very reliable. Also ALi (Acer Laboratories, Inc.) returned to the big business with their MaGiK-1 chipset with DDR support. Last but not least AMD is shipping their AMD-760 chipset for Socket A and DDR memory interface.

The workstation and server market has not been served by AMD so far, as there is still no chipset for dual Athlon systems available. That gap will hopefully be closed by summer 2001 with the AMD-760MP chipset.

Current Athlon Prices

The following table contains the current average Athlon prices (ascertained over www.pricewatch.com).

The currently ‘slowest’ models are priced very attractively, which makes them much more interesting than most Pentium III models between 800 and 933 MHz. As you could read in previous articles (check the Keyword Index or CPU Guide), the Athlon Thunderbird outperforms Intel’s Pentium III due to its clock speed advantage. The AMD CPU is even able to beat Intel’s Pentium 4. Please read Tom’s Power Box article where he overclocked an Athlon-C to amazing 1.6 GHz!

Test Setup

As I wanted to show the difference between the various processor speeds, I used a fast graphics card, NVIDIA’s GeForce 2 Ultra. It is one of the fastest 3D boards available, but still the bottleneck in some of the benchmarks.

You should be quite familiar with the rest of the test setup: IBM’s DTLA drive, Asus A7V133 and 128 MB brand SDRAM by Wichmann Workx Germany.

SYSmark 2000: Windows 98 SE

The 50% clock speed increase from 800 to 1200 MHz leads to a performance gain of almost 35%. That is quite a good result. This good scaling makes clear that the Athlon architecture is far away from exhausted. I guess we will be seeing lots of future CPUs based on the Athlon architecture.

Mercedes Benz Truck Racing

We already indicated MBTR several times to be a very demanding 3D game. Actually there are only few game titles available that are really able to give fast graphic cards a hard time. 1024×768 has become some standard for most users today, which is why I decided to use this resolution here. The differences are very small, showing without any doubt that the processor does not have too much influence on those results. The graphics card is definitely the bottleneck.

Quake III Arena: 1024×768

One of the most widely used benchmarks is Quake III Arena. At the resolution of 1024×768, the test system is able to score blazing frame rates. Even when switching to 32 Bit and maximum details, you will not see any of those processors providing less than 75 frames/s on our test machine.

It is rather questionable if one really needs an Athlon 1200 to get more than 150 fps, as long as an Athlon 800 is pretty much fast enough as well. Let’s increase the resolution.

Quake III Arena: 1600×1200

Again the results are limited by the fill rate of the graphics card. At least we found out that the CPU does not play the chief part for 3D gaming today.

SPECviewperf 6.1.2: Advanced Visualizer

You can see quite well that the new Athlon C-models are definitely able to benefit from the higher Front Side Bus speed of 133 MHz: E.g. an Athlon-C 1000 scores as well as a standard model at 1100 MHz.

SPECviewperf 6.1.2: Design Review

Design Review is even more sensitive to CPU bandwidth. The Athlon-C 1000 is even faster than an 1100 MHz model at 1200 MHz core speed. People with high demands to OpenGL applications should definitely go for one of those new CPUs.

SPECviewperf 6.1.2: Data Explorer

Again the new Athlons for 133 MHz FSB clearly outperform their brothers. The difference between the standard Athlons is hardly noticeable, as you can see from the results of the 800, 900 and 1000 MHz Athlons. As soon as you increase the FSB speed, the Athlon is able to show more of its potential.

SPECviewperf 6.1.2: Lightscape

Here you can see only a little performance advantage of the new Athlon-C. Lightscape primarily wants core clock.

SPECviewperf 6.1.2: MedMCAD

MedMCAD scales very linear. Higher clock speeds will accelerate your system noticeably. This time, the 133 MHz FSB of the new Athlons does not have such an impact.

SPECviewperf 6.1.2: ProCDRS

ProCDRS seems to be limited by the graphics card, as the performance gains decrease when increasing the clock speed. Getting an Athlon 1000 instead of the 800 MHz model is definitely a good idea. Taking the 1.2 GHz type instead of the 1.0 GHz will give you a smaller thrust.

Price/Performance

Last but not least we are taking a look at the price/performance ratio. The provided CPU performance is not able to keep pace with the higher prices of the high speed models, making the 800 and 900 MHz models the best performers per $ right now.

We normalized the performance of the Athlon 800 as well as its performance/price ratio to 100. You can see that as the performance increases with faster Athlon models, the performance/price index drops, because the price difference between the Athlon processors is larger than their difference in performance. It is interesting to see that the ratio remains almost the same around 50, starting with Athlon-C 1000. This means that you get almost the same amount of performance for your money if you buy Athlon-C 1000, Athlon 1100, Athlon-C 1133 or Athlon 1200 and Athlon-C 1200. Still the best performance per buck is – as expected – found in the slower models Athlon 800 and Athlon 900.

The picture changes if you use the Athlon 800 as a reference point and check how much more performance you get for how much more money compared to the Athlon 800.

I was surprised myself when I saw that after the Athlon 900, which asks for $5.72 more money per percentage point of performance increase, the Athlon-C 1200 comes in No.2 with $6.65 per percentage point of increased performance compared to an Athlon 800. The 6.4% more performance of the Athlon 1000/100 is the most expensive, asking for $11.01 per percentage point. This unusual and maybe somewhat difficult chart shows that in comparison to the Athlon 800, the performance of the current top-model Athlon-C 1200 is not that expensive at all.

Conclusion

It still is a fact that buying fast CPUs does only make sense if you

• have rather unlimited funds
• know what you are spending the money for
• and really require highest performance

I guess most of you do not have an unlimited budget to spend for computer components, which is why there are some things to consider before choosing a processor speed:

• Check your requirements!
  
  If you already know that you are only going to surf the Internet and run office applications, you should even consider the inexpensive Duron. High-end benchmarks like the SPECviewperf usually benefit from a fast CPU, but not the standard software.

• Games will run best if you team up a mid-range CPU like an Athlon 800-1000 with a fast graphics card. 3D enthusiasts should not pair a Gigahertz CPU with a mediocre 3D-card like a TNT2/Ultra, Matrox G450 or S3 Savage2000. Try to use a GeForce 2 model at least (MX, GTS, Pro, Ultra).
• The impact of processor price drops is always tremendous, ensuring that your new investment will lose its value rather rapidly. If you save money by purchasing a mid-range Athlon, you still have the option to upgrade to a faster one. Modern motherboards come with advanced voltage regulators, which could easily supply lower voltages (e.g. 1.3 V) for future Athlon cores.
• Higher clock speeds come hand in hand with more heat, which you have to tackle with a huge heat sink and a powerful fan. The best CPU coolers are partially or entirely made of copper, resulting in formidable prices. In addition, big fans make more noise than smaller ones. Please refer to the recent CPU cooler review.