Standard Disclaimer: I am not affiliated with Chaintech in any way, shape, or form. The opinions expressed here are mine.

Introduction

The goal was to build a Windows NT 4.0 workstation. I wanted to offload all of my web development from my client PC in addition to having the added luxury of a file and print server. I needed a mainboard to power a Cyrix 6x86MX PR200. The Chaintech 5SDA, based on the new SIS 5598 chipset, looked right for the job.

In the US, Chaintech is a relatively unknown Taiwanese based mainboard manufacturer. According to the Chaintech company information page, Chaintech is one of the top 10 producers of PC mainboards in Taiwan. They are ISO-9002 certified. The best recognition of their products to date was in 1996 when they received the highest score on C'T magazine's evaluation of Pentium-class mainboards. Although I was familiar with the name Chaintech, I had no prior knowledge of how their products performed. A quick search for Chaintech on Dejanews, however, does reveal a significant amount of newsgroup discussion of their products.

For additional general information about Chaintech and their products, check out their website at www.chaintech.com.tw. They also have a mirror site located in the US at www.chain-tech.com, but it seems to be updated infrequently. I suggest using the Taiwanese site.

Chaintech 5SDA Specifications

Other Highlights:

• Embedded 64-bit SVGA Chip
• Supports Cyrix/IBM 6x86 PR120+ - PR200+ (processor rev. 2.7 or later)
• Supports Cyrix/IBM 6x86MX PR166 - PR233 processors
• Listed on the Cyrix 6x86MX motherboard compatibility list
• Provides up to 128MB DRAM cacheability
• Designed to run the Cyrix/IBM 6x86 and 6x86MX with Linear Burst Mode support
• PCI Asynchronous Mode for 50/75/83 MHz bus speeds
• High-efficiency switching voltage regulator
• ATX power supply connector supports software power off control and override power button
• Supports PIO Mode 4, Multi-word DMA Mode 2 and Ultra DMA-33 timings
• Award BIOS

The Out of Box Experience

Three things stood about this board after I took it out of the box:

1. Included with the board is a VGA extension card with two optional USB ports. The card fits in the USB & VGA port that is located between the SIMM and PCI slots. The card must be installed if you are going to use the onboard VGA or USB features of the mainboard.
2. There are two power connectors included on the board. There is an ATX power connector in addition to the standard AT power connector for the AT form factor. This is a very intriguing feature. It prevents you from having to throw away the board if you decide to upgrade to an ATX case. However, if Chaintech is using it to alleviate the need for a ATX version then I think that it is a bad idea. I prefer the ATX form factor because of its design layout rather than its power features.
3. Chaintech decided to implement dip switches rather than jumpers to manipulate the motherboard configuration settings. Although I prefer dip switches because they are easy to access and less confusing than jumpers, the dip switches themselves are so small they can be difficult to set.

The motherboard documentation is excellent. I loved the fact that they included a quick connector and dip switch reference guide in the center of the manual. This reference guide was all I needed to get the board configured. Even if you are a novice, there is more than enough information included within the manual to get the mainboard installed.

Chaintech, like most mainboard manufacturers didn't dedicated any coverage to the BIOS chipset features setup options in the manual. They suggest that you visit Award for this information and only change it if you are absolutely sure of what you are doing. This advice will cutback on the number of Chaintech technical support inquiries because the BIOS settings are set for safe performance by default, but if you follow this advice you will be left with less than optimal system performance.

Also shipped with the board is a CD-ROM that includes the bus mastering drivers and VGA drivers for the onboard SVGA accelerator. Drivers for all of the most popular operating systems are included on the CD-ROM. Chaintech also threw in some free software for fun, but none of it is worth mentioning.

The Good

The Via Apollo VP2 (AKA AMD 640) isn't the only viable alternative to Intel's TX chipset. The SIS 5598 and its sibling the SIS 5582 are also candidates for the job. The SIS 5598 supports SDRAM and Ultra DMA. The SIS 5598 will cache up to 128MB of DRAM whereas the Intel TX chipset will only cache up to 64MB of DRAM.

The Chaintech 5SDA is listed on the Cyrix 6x86MX motherboard compatibility list and supports the linear burst mode feature of the 6x86 and 6x86MX.

The Chaintech 5SDA supports 50/55/60/66/75/83 MHz bus speed and offers a special PCI asynchronous mode for 50/75/83 MHz system frequencies. This means that the PCI bus is running at 33 MHz at 50/75/83 MHz system frequencies instead of 1/2 the system clock. As a result, you are not underclocking the PCI bus at 50MHz or overclocking the PCI bus at 75MHz and 83MHz. This has been an issue with most overclocked Pentium boards because of the Pentium architecture's synchronous operation with the PCI bus. A lot of PCI cards don't like being overclocked and will misbehave at 75MHz and 83MHz system frequencies.

The SIS 5598 integrates a high-performance 64-bit DRAM-based graphics/video accelerator. If you are trying to build a system for the least amount of money possible, you can save yourself some cash by utilizing the onboard 64-bit SVGA accelerator instead of buying a dedicated one.

The Bad

The Chaintech 5SDA is stingy when it comes to ISA and SIMM slots. With only three ISA slots, it is not the most expandable mainboard on the market. Personally, I prefer four.

The availability of only two SIMM slots is EXTREMELY limiting. You will be throwing away memory if you want to upgrade from 16MB to 32MB or 32MB to 64MB of EDO DRAM. Once again I prefer a mainboard that has four.

If you decide to use the embedded 64-bit SVGA chip you will be sharing system memory with the video buffer. There is a BIOS option where you can select from .5MB to 4 MB of system memory to share. This isn't a big deal if you have a lot of system memory, but it is definitely less than optimal if you only have 16MB or less.

The Upgrade

This upgrade should of and could of been a snap had it not been for one huge problem that was very difficult to track down. It was one of the last things that I tried during my troubleshooting effort. I had to underclock my Cyrix 6x86MX PR200 before I could get the system to run. When I configured the mainboard to run my 6x86MX PR200 166MHz (2.5 x 66MHz) the system did nothing. I didn't receive post codes from the BIOS or a video signal from the video card. It just looked at me stupid. I tried everything to get the board running and I had almost decided that the board was dead before I underclocked the CPU to 150MHz (2 x 75MHz) as a last resort. That did the trick.

I was literally amazed because the same chip had been running at 166MHz (2.5 x 66MHz) perfectly in my Abit AX5 thirty minutes earlier. Thinking that I had damaged the CPU in the process of transferring it, I put it back into my AX5 and it worked perfectly at 166MHz as it did before.

The mainboard also sometimes refused to auto-detect my Maxtor 2.0 GB ATA-2 harddrive when I did a soft restart. A soft restart would include a ctrl-alt-delete or selecting the Restart the computer option from the Windows NT shutdown menu. In order for the system to auto-detect the harddrive, I had to perform a hard restart which entails using the reset switch or powering off and on the machine.

I can't explain these behaviors. I decided that I would put Chaintech technical support to the test. Maybe someone there could suggest something else to try. I submitted the problem that I was having to them and I received a standard form letter reply informing me that they were working on my problem. I haven't heard back from them since.

The BIOS

The Cyrix 6x86MX-PR200 (2 x 75MHz) was not correctly identified by the BIOS as a 6x86MX PR200 during POST. The BIOS thought that I was using a 6x86MX PR166. Chaintech has not released an upgraded BIOS to resolve this cosmetic issue that occurred as a result of the recent 6x86MX PR rating modifications recently implemented by Cyrix/IBM.

The Onboard SVGA Accelerator

With the cost of quality 4MB video accelerators approaching $100, I recommend using a dedicated video accelerator instead of the onboard SVGA accelerator. The performance hit just isn't worth it unless graphics performance is not important to you at all. The onboard SVGA accelerator performs admirably as long as you are using a low resolution (640x480 or 800x600) and very few colors (256 or less). I adjusted my video settings to 1024x768, 16-bit color, and 75MHz refresh rate. This brought the onboard accelerator to its knees. It was begging for mercy and the performance drop was very noticeable.

Windows NT 4.0

This is the second time that I have built a Windows NT 4.0 system that was powered by a Cyrix/IBM CPU. The most that I have to say about this is that it was uneventful. Everything worked fine and all of the NT 4.0 drivers that Chaintech included on their CD-ROM worked like a champ.

Benchmarks

Benchmarks were performed on the following system. Here is a summary features:

• Cyrix 6x86MX PR200
• Chaintech 5SDA, Bios 06/17/1997
• 30 MB 50ns Micron EDO Memory
• 512 KB Synchronous Pipeline Burst Cache
• Onboard 64-bit SVGA 2MB EDO RAM (1,024-by-768, 16-bit color, small fonts, 75MHz refresh rate)
• Maxtor 2.0 GB Fast ATA-2 / PIO Mode 4
• Windows NT Build 1381 (SP3)

I wanted to show and compare benchmarks of the Chaintech 5SDA and Windows NT 4.0, but I was never able to complete the Business Winstone 97 benchmark. I tried and failed many times using the default BIOS settings with both 32MB 50ns Micron EDO DRAM and 32MB 10ns AMC SDRAM. Micron memory is some of the highest quality and most stable memory in the world. This was disheartening to say the least.

Key Learnings

In my humble opinion, the SIS 5598 and its sibling the SIS 5582 look like very promising chipsets. Unfortunately, the Chaintech 5SDA implementation of it is a poor one. I recommend against purchasing the Chaintech 5SDA. Mine just had to many serious problem. This, however, is not a blanket statement against Chaintech. I am sure that they have other quite capable products.

M-Tech has just released their new Mustang - Ultra R542 and R547 which also use the SIS 5598 and SIS 5582 chipset. The R542 offers many of the same features as the Chaintech 5SDA. Let's hope that M-Tech with their history of offering Cyrix optimized mainboards provides a better implementation.

This page has been accessed times since Monday, September 22, 1997.