Related story: AMD Duron-Benches up to 750 MHz in English
At the Computex trade show in Taiwan from June 5 to June 9, the VIA stand was bustling with people. Much to everyone's surprise, the company announced on the second day of the show that it would ship the Cyrix III with a new core. This announcement confirmed what was rumored before: the CPU developed under the code name "Joshua", which had been delayed several times, was finally cancelled due to lack of performance. VIA stated that they would launch their first CPU featuring the Samuel core, originally developed by IDT. In summer 1999 VIA had acquired IDT. The IDT team, now working for VIA, was three months ahead of its schedule. VIA therefore decided to give up the Joshua core the Cyrix team was working on. However, VIA kept the name of "Cyrix III" in order to avoid wasting the money the company had already spent on the marketing campaign. But from a technical point of view, the "Cyrix III" has nothing to do with Cyrix anymore.
The Cyrix III fits into the Socket 370 and is claimed to be fully compatible with the Celeron in its PGA packaged version. The new CPU targets the cut-price market and will initially be available at clock speeds of 500 and 533 MHz, with the FSB clocked at either 100 or 133 MHz. It also features AMD's 3DNow! instruction set and MMX. The cache design of the Cyrix III is rather unusual: while it does have two 64 KByte L1 caches for instructions and data, it lacks an L2 cache.
Our comprehensive benchmarks reveal if VIAs new arrival can beat its AMD and Intel competitors with this design.
Details on the Cyrix III
VIAs Cyrix III is the first non-Intel CPU designed for the P6 bus. This means that the Celeron will have a competitor fighting for its socket. Due to patent issues, other manufacturers have not been permitted to produce P6 clones so far. VIA works around this problem just as with their chipsets, i.e. the company signed cross-licensing agreements with National Semiconductors, who also produce some of the CPUs. National in turn has entered into comprehensive cross-licensing agreements with Intel and is therefore allowed to use the protocol of the P6 bus. National, moreover, was the previous owner of Cyrix before VIA acquired the chip maker.
Originally Cyrix III was designed to include the Joshua core, which was based on the Cyrix M2 technology. Key features included a 64-KByte L1 cache, an 256-KByte L2 cache and two pipelines for the FPU und MMX units. The FSB was designed to be clocked at 133 MHz.
Quite a number of changes have been made in this respect on the final Cyrix III with the core of the WinChip-C5A (aka Samuel). The CPU now has an L1 cache with a total of 128 KBytes. The design, which is based on the Winchip 4 (Socket 7), splits this L1 cache into two 64 KBytes sections for instructions and data. But the CPU socket is not the only difference between the Cyrix III and the WinChip 4. However, VIA has not disclosed many details on the architecture of the Cyrix III. The company only stated that Cyrix III had a 12-stage pipeline. The WinChip-4 came with only 8 stages for its pipeline.
Our analysis revealed another difference. Both parts of the L1 cache only work with 4-way associativity. This was originally planned by IDT for the data cache only. Much like the WinChip-4, the TLBs (translation look-up buffers) of the Cyrix III can hold 128 entries and work with 8-way associativity. Please refer to our feature on Processor Basics in the Cache Basics section for detailed information on associative caches. The feature is currently only available in German - please bear with us.
In general, the IDT team led by designer Glenn Henry keeps to their basic concept: a highly integrated core and a simple architecture make for a small die. Leaving out the L2 cache completely is unusual, though. This must be the tribute paid for the low price of the CPU. Only the successor to the current Cyrix III (code name: Samuel 2) will have a 64 KB L2 cache.
Low power dissipation
Despite the lack of an L2 cache, VIA's Dynamic Power Caching Architecture is designed to ensure an optimum balance between high performance and low power dissipation. This marketing jargon describes a simple idea: sacrificing the L2 cache reduces the number of transistors and total power consumption. At 10.5 W max under heavy load and 2 W when idle (both figures apply to the 533 MHz version), the Cyrix III is a rather modest CPU. The core voltage is specified at 1.9 V. These figures make VIA's CPUs an interesting option for notebooks, too. VIA intends to offer special versions of the processor under the name of "Cyrix III LP" with PGA and BGA packaging for mobile computers soon. Here as well, VIA plans to ensure full compatibility with the Celeron for easy implementation in existing machine designs.
One reason for the low power consumption of the Cyrix III is the advanced 0.18 micron manufacturing technology. The Cyrix III is therefore able to hold 11.2 million transistors in one die of only 72 square millimeters in size. This die is made of six metal layers. To put these numbers into perspective: the Celeron 566 at 0.18 micron has a die of 104 square millimeters, which holds 9.5 million transistors for the core and the L1 cache plus an additional 9.3 million transistors for the integrated L2 cache.
In addition to its MMX instructions, the Cyrix III also features the 3DNow! instruction set by AMD. The processor runs its FSB at either 100 MHz (Cyrix III 500) or 133 MHz (Cyrix III 533). VIA intends to ship the Cyrix III with a locked multiplier, which leaves little scope for overclocking.
With the new CPU VIA does not continue its tradition of "PR rating" a processor, which did not specify the exact clock speed but the performance in comparison to an Intel chip at the PR rated clock speed. For the Cyrix III, the given clock speed spells real megahertz.
Pricing and Availability
The Cyrix III is claimed to be available at clock speeds of 500 and 533 MHz right from the start. VIA already ships limited quantities to major distributors. Full mass production will ship into the Asian/Pacific region first since low-cost CPUs are of greater importance there. Larger quantities for Europe are expected for the end of June or beginning of July. VIA intends to supply a total of 150,000 Cyrix III processors in June 2000.
Originally VIA planned to start mass production of the Cyrix III at clock speeds of up to 667 MHz. However, this production schedule had to revised at short notice due to high reject rates. The roadmap now schedules the end of October 2000 as the delivery date for a Cyrix III at 667 MHz. It is likely though as yet unconfirmed that a 733 MHz version will also be available by this date.
Clock Speed (MHz) | 1Ku Tray Units, USD | Available |
|---|---|---|
Last revision: 14.06.00 | ||
500 | 50 $ | Now |
533 | 75 $ | Now |
566 | tba | August/September |
600 | tba | August/September |
667 | 160 $ | October/November |
VIA's next generation of microprocessors is currently scheduled for the first quarter of 2001. The CPU (code name: Samuel 2) is based on a modified WinChip-C5B core. It will feature a 128-KByte L1 cache and a 64-KByte L2 cache. VIA claims clock speeds from 667 MHz upwards. The second quarter of 2001 will see Samuel 2 at 800 MHz. It will then replace the Cyrix III.
Benchmark Setup
We ran the Cyrix III with an Epox EP-6VBA2 motherboard and Solteks SL67KV. Since these are boards for Slot 1, we used a Soltek S370 adaptor. The Cyrix III was recognized as a Celeron by the Epox board and as a "VIA Samuel" by the Soltek product. This means that at least the Epox board did not have an adapted BIOS at the time of our review. According to VIA there was no necessity for a modified BIOS since the Cyrix III was 100 per cent compatible with the Celeron. Nevertheless, we verified the results with Tyans Trinity 400 S1854 (Socket 370), which also identified the Cyrix III as a Celeron.
As far as the performance of the Cyrix III processors is concerned, VIA points out that adapted BIOS versions are designed to use the large L1 cache of the Cyrix III more efficiently. Memory scores will increase by up to 10 per cent, its overall performance (SYSmark98) by 2 or 3 per cent, the company says.
In our benchmarks we were not able to ascertain any significant performance differences between the Soltek SL-67KV and the Epox EP-6VBA2.
We reviewed the production silicon of a Cyrix III 500. This CPU works with a 100 MHz FSB and has its multiplier locked at 5x. By increasing the FSB clock to 133 MHz, we were able run the processor at 667 MHz, using additional cooling. Therefore we are now able to present the scores of the Cyrix III 667, which is expected to ship around October or November.
2D-Benchmarks: Windows 98SE
The level of performance with standard applications is still the most important issue for a microprocessor. This does not only include programs such as Microsoft's Word or Excel but also MPEG encoders, 3D and sound-editing applications. Chip makers simply love computer games since this market is always in need of greater CPU performance. The Internet has also been identified as one of the potential drivers for faster CPUs, however, practical experience has shown that SSE or 3DNow! do not make much of a difference when it comes to surfing the Internet.
Apart from a few exceptions, classic 2D applications gain the most from a CPU that performs well with integer instructions. But the number of sound and graphics editing applications that - just as games - prefer a fast FPU and MMX or 3DNow! is constantly increasing. We therefore evaluated the performance with the benchmark suite SYSMark98 by Bapco, which features a mix of all the aforementioned applications.
Cyrix III does not offer satisfying performance with standard applications and Windows 98SE. The lack of an L2 cache has a considerable negative impact on the scores. For a direct comparison of the Intel and VIA cores, we also benchmarked a Celeron 500 with the L2 cache disabled. The Celeron clearly wins with 136 points versus 103 points achieved by Cyrix III. This is even more significant since the Celeron only has a 32-KByte L1 cache, split into 16 KBytes each for instructions and data. The Samuel core is not even able to match the Celeron core under "equal conditions".
Please bear in mind that "PC100" and "PC133" in these diagrams only refer to the memory clock. The Celeron 566 always ran at its specified FSB of 66 MHz while the FSB for the Cyrix III 500 was clocked at 100 MHz.
2D-Benchmarks: Windows NT 4.0
Since VIA positions the Cyrix III as a low-cost solution, the performance of this CPU under Windows NT is not necessarily the decisive issue. Running these benchmark tests, however, shows whether the CPU was optimized for a particular operating system.
SYSmark98 with Windows NT produces equally poor results for the Cyrix III as under Windows 98. The Cyrix III 500 is only a little more than half as fast as the Celeron at the same clock speed. It does not even match the performance of the AMD CPUs for Socket 7, which have a lower clock rate.
Please bear in mind that "PC100" and "PC133" in these diagrams only refer to the memory clock. The Celeron 566 always ran at its specified FSB of 66 MHz while the FSB for the Cyrix III 500 was clocked at 100 MHz.
3D-Benchmarks: 3D-Mark99 Max Pro
The synthetic 3D benchmark 3Dmark99 Max Pro serves as a touchstone for the capacity of the Intel 3D instruction set (SSE) and AMD's 3DNow! as it is implemented in the Cyrix III. 3Dmark99 also lends itself to comparing the performance of a processor's FPU and the 3D instruction set. And it can be run with or without being optimized for a particular instruction set. It therefore is well suited for comparing CPUs.
The final score obtained with 3Dmark99 Max Pro strongly depends on the graphics system. However, since we always use the same graphics boards, drivers and settings for each CPU, any factors that might lead to distorted results are excluded.
The rather weak FPU performance of the Cyrix III may be due to the design of the original WinChip-4. Unless VIA has made significant changes here, the FPU still must be running at half the clock speed of the core. In addition, IDT's implementation of the 3DNow! instruction set used to be less than optimal before. It seems that the Cyrix III has also inherited this weakness.
Please bear in mind that "PC100" and "PC133" in these diagrams only refer to the memory clock. The Celeron 566 always ran at its specified FSB of 66 MHz while the FSB for the Cyrix III 500 was clocked at 100 MHz.
3D games: Quake 3 Arena
3D games with an ever greater degree of complexity use PC hardware to the max. FPU performance is critical here, and this has always been a weak point with Cyrix processors. Quake III completely relies on OpenGL. A high polygon count and complex environments are the main technical characteristics of the graphics of this 3D game.
Please bear in mind that "PC100" and "PC133" in these diagrams only refer to the memory clock. The Celeron 566 always ran at its specified FSB of 66 MHz while the FSB for the Cyrix III 500 was clocked at 100 MHz.
3D games: Unreal
The old Unreal is an especially suitable 3D benchmark. We took the scores using Direct3D. Unreal also features a very advanced soft renderer that does not use the 3D capabilities of the graphics board and heavily depends on FPU and MMX performance.
Please bear in mind that "PC100" and "PC133" in these diagrams only refer to the memory clock. The Celeron 566 always ran at its specified FSB of 66 MHz while the FSB for the Cyrix III 500 was clocked at 100 MHz.
Conclusion
In the past, Cyrix processors were well known for three things: low price, weak FPU performance and excessive power dissipation. Although the Cyrix III only has the name in common with these classic Cyrix chips, two of the weak points mentioned have been passed on to the Cyrix III:
The rather disappointing performance of this new CPU is in line with the poor record of previous Cyrix processors. It is not only the fact that the FPU performance is so dissatisfying that the Cyrix III has to be labeled as a "Don't buy!" product for gamers. What is even worse for the overall system performance is the weak integer performance of the Cyrix III. Its AMD and Intel competitors are so far ahead of the Cyrix III that it is impossible to overlook the weaknesses of the new chip. The concept of the Samuel core, which consists in making up for the lack of an L2 cache with a big L1 cache, simply does not work when it comes to real world performance.
In order to play fair, one has to bear in mind VIA's overall strategy, i.e. the Cyrix III strictly targets the cut-price segment of the market. And the low price is the good part of what the Cyrix III inherited.
At 50 US dollars for the Cyrix III with 500 MHz, this chip is currently about half as expensive as a Celeron at the same clock speed. This is a great advantage for the Cyrix III, which has been designed for launch into a highly competitive market. It seems clear that this CPU will make its way into low-price office machines and PCs that are only used for Internet access at home. There are also a lot of countries in the world that regard the price of personal computer as the top priority. It is not by coincidence that VIA intends to ship large quantities to the Asian/Pacific region first.
By way of a last positive finding, we have to state the Cyrix III is fully compatible with Socket 370. Our tests have also shown that the CPU runs rock solid. Even the high power dissipation of Cyrix CPUs has gone with the Cyrix III so that the current chip and especially its future low power versions may be a good choice for notebooks. (cvi/nie)
(Translation by Isolde Gassner and Nico Ernst. This story is (c) 2000 by IDG Interactive GmbH. All rights reserved.)
Test Setup - Software
We review microprocessors with a strictly defined setup. The following applies to the software used:
Bapcos SYSmark98 runs at a 1024x768 resolution with 32-bit colors. The operating systems used are Windows 98 SE (Second Edition) and Windows NT 4.0 with Service Pack 5.
With 3DMark99 Max Pro we use a 800x600 resolution at 16-bit colors with triple frame buffering (default settings of this benchmark).
The Unreal scores give the frames per second when running the initial timedemo of the game after at least three complete runs (timedemo 1). The game runs at 800x600 resolution and 16-bit colors. We both give the scores for 3D acceleration by the graphics board with Direct3D and with software rendering ("unreal - nohard")
The demo version of Quake 3 Arena is used with demo2 at the normal detail level at 640x480 resolution and 16-bit colors.
V-sync is disabled for all gaming and 3D benchmarks.
Test-Setup - Hardware
The following gives a detailed listing of the hardware we use for reviewing CPUs:
Component | Type |
|---|---|
| |
CPU | VIA Cyrix III |
Clock Speed | 500 MHz |
Socket | S370 |
Microcode | 660/00 |
Mainboard 1 | Soltek SL-67KV |
Serial No. | 9911000T000398 |
Firmware | F5 |
Noteworthy | Slot 1 |
Mainboard 2 | Epox EP-6VBA2 |
Serial No. | 9912044657 |
Firmware | 0414 (14.4.2000) |
Noteworthy | Slot 1 |
Mainboard 3 | TyanTrinity 400 S1854 |
Serial No.. | TY0971010041 |
Firmware | v1.7 |
Noteworthy | Slot 1 /S370 |
Mainboard 4 | Soltek SL-56G2 |
Serial No. | 9911000T000492 |
Firmware | 56G-Z4 |
Noteworthy | Super Socket 7 |
Mainboard 5 | AMD FESTER B3 |
Serien-Nr. | 090799FL0047 |
Firmware | aftb00-9 23.11.99 |
Noteworthy | Slot A |
RAM 1 | SEC KM48S8030AT |
Serial No.. | --- |
Firmware | --- |
Noteworthy | 128 MByte SDRAM PC100 CAS=2 |
RAM 2 | 128MB PC133 |
Serial No. | 241197 |
Firmware | --- |
Noteworthy | 128 MByte SDRAM PC133 CAS=3 |
Soundboard | TerraTec XLerate Pro |
Serial No. | 1293900011590 |
Firmware | --- |
Noteworthy | Rev. C / 4.06.2016 / 13.03.1999 |
Network Adaptor | 3Com Fast Etherlink 3C905B-TX |
Serial No. | 6TQ2E9F603 |
Firmware | Hardware-Rev.: 048 |
Noteworthy | Rev. A / 4.10.2222 / 05.05.1999 |
Graphics Board | Guillemot Maxi Gamer Xentor 32 |
Serial No. | 905381151072 |
BIOS | V2.05.13 |
Noteworthy | Detonator 5.16 |
SCSI-Adaptor | Adaptec AHA-2940UW Pro |
Serial No. | BC0B90905QN |
Firmware | V.2.11.0 |
Noteworthy | V2.21A |
Harddisk | Quantum ATLAS IV 9 WLS |
Serial No. | 369919430210 |
Firmware | 0808 |
Noteworthy | 8,7GB REV 01-D |
DVD-ROM | Pioneer DVD-303S-A |
Serial No.. | TGT0059423WL |
Firmware | 1.09 |
Noteworthy | --- |
Power Supply | Channel Well Technology ATX-230 |
Serial No. | 540299070595 |
Firmware | --- |
Noteworthy | 230 W |
Keyboard | Cherry RS 6000 M |
Serial No.. | G 0064318 4 L28 3 I |
Firmware | --- |
Noteworthy | --- |
Mouse | Logitech M-S35 |
Serial No.. | LZA84352013 |
Firmware | --- |
Noteworthy | 3 Keys :) |