New BIOS Available!

Use the following directory to find information on getting the most out of your S1571:

Unsupported Processors - (updated 9/16/01)
Tyan bios v1.06 - New J.2 Patch! - (updated 9/16/01)
Jumper Settings
System Ram
Overclocking
Win95 K6-2/350+ Bug
Utility Programs - (updated 9/16/01)
Disclaimer

Intel

Since the P55C 233 was the last Intel socket 7 processor (the Pentium II's are all of the slot 1 type), none of the upper end Intel processors will work in the S1571 motherboard.

Important!! The Intel Celeron processors will NOT work in the S1571. The Celeron was designed for use in a socket 370 board, NOT a socket 7 board!

Cyrix

The S1571 manual only lists Cyrix processors up to the PR233 M II. However, the upper end Cyrix M II processors will work with the S1571 motherboard.

Important! The following notes are a few things you should know about Cyrix M II processors before you decide to install one in the S1571.

First, a note concerning the "PR" numbers on Cyrix processors. These are what Cyrix calls "performance ratings" and are NOT an indication of actual processor speed! For example, the M II-333 is designed to run at a bus speed of 83mhz with a 3.0 multiplier. This gives you an internal speed of only 250mhz, not 333mhz. The following chart shows the Cyrix recommended bus and multiplier settings with the ACTUAL internal frequency shown in red:

Processor	Clock Mult.	Bus Freq.	Actual Freq.
M II - 266	x2.5	83mhz	208mhz
M II - 300GP	x3.0	75mhz	225mhz
M II - 300GP	x3.5	66mhz	233mhz
M II - 333GP	x3.0	83mhz	250mhz
M II - 366GP	x2.5	100mhz	250mhz

The third multiplier pin, BF2 (Cyrix calls it CLKMUL2), is NOT functional on the M II processors. This means that the highest multiplier you can get with these processors is x3.5. If you look at the Jumper Settings section on this page, you will notice that the x4 through x5.5 multiplier settings ALL use the BF2 pin.

All Cyrix M II processors use a core voltage of 2.9v and an IO voltage of 3.3v.

AMD

Many of the upper end AMD processors will work perfectly with the S1571 motherboard. This includes ALL of the K6 and many of the K6-2 models.

AMD K6
AMD K6-2 (up to 333mhz)
AMD K6-2 (350mhz and above) - (updated 9/16/01)
AMD K6-III - (updated 9/16/01)
AMD Mobile K6-2+/K6-III+ and "E" processors - (updated 9/16/01)

AMD K6

All of the AMD K6 processors will work with S1571. The v1.03 bios that comes with the S1571 supports the K6, but may not properly recognize the the models above 233mhz. For the rest, simply set the bus speed, CPU multiplier, IO voltage, and core voltage to the proper settings. All of the AMD K6 processors use a 66mhz bus speed and an IO voltage of 3.3v. However, the core voltages differ between different models. This should be clearly marked on the top of the CPU. If not, here's a list of the K6 processor core voltages:

Model 6 processors:
AMD-K6-166ALR -- 2.9v core
AMD-K6-200ALR -- 2.9v core
AMD-K6-233ANR -- 3.2v core

Model 7 processors:
AMD-K6/200AFR -- 2.2v core
AMD-K6/233AFR -- 2.2v core
AMD-K6/266AFR -- 2.2v core
AMD-K6/300AFR -- 2.2v core

Note the use of the ' - ' between the "K6" and the "233" with the model 6 and the use of the ' / ' with the model 7. The "F" in "AFR" denotes a 2.2V core.

Point of interest: The model 6 uses .35 micron process technology and the model 7 uses .25 micron. This allows for the lower core voltage in the model 7.

AMD K6-2 (up to 333mhz)

Even though they are designed for the "super" socket 7, most of the AMD K6-2 processors will work with the S1571. The only important differences between the socket 7 (what the S1571 uses) and the "super" socket 7 is support for a 100mhz FSB (front side bus) and AGP. Since the S1571 doesn't even have the hardware for either of these, it doesn't matter. There are no other limitations with using a K6-2 in a socket 7 motherboard. I'm using a K6-2/333 in my S1571 right now and it's working great!

The v1.03 bios that comes with the S1571 does NOT support the K6-2, so you will need to upgrade your bios to the v1.06 bios available for download from Tyan. The v1.06 bios not only allows your system to properly recognize the K6-2 (the v1.03 bios labeled my K6-2/333 as a 486 at 66mhz), but it also allows for support of some of the advanced features of the K6-2. All you need to do, besides updating your bios, is to set the bus speed, CPU multiplier, IO voltage, and core voltage to the proper settings.

Important!! ALL of the AMD K6-2 processors use a 66mhz bus speed when used in the Tyan S1571. This includes the 95 and 100mhz bus models! (See the section on overclocking for more information on faster bus speeds.)

AMD K6-2 (350mhz and above)

The information presented in the above AMD K6-2 (up to 333mhz) section also applies to most of the K6-2/350 and higher processors. However, there are some differences and possible problems that need to be mentioned.

First, any AMD K6-2/350 or higher system that is running Windows 95 WILL become unstable. I explain this problem in full detail in the Win95 K6-2/350 Bug section of this web page.

Note: You will need to enable the "Write Allocate" feature on certain versions of the K6-2 processor. The updated v1.06 bios enables the Write Allocate feature on the K6-2 model 8/[7:0], but doesn't seem to enable it on the K6-2 model 8/[F:8] (CXT core), which includes the K6-2/400. Although the system will run fine without this option enabled, it will not perform as well as it should. The Write Allocate feature can be enabled on the K6-2 model 8/[F:8] by using either the "Setk6" program or updating to the J.2 patched bios. I have made both of these files available for download in the utility programs area of this page.

In the following paragraphs, I will list each AMD K6-2 processor at 350mhz and above separately and address any problems related to each.

K6-2/350 and 380
The problem with using these processors on the S1571 is that you can't actually run these speeds. For example, the K6-2/350 was designed to work on a motherboard with a 100mhz Front Side Bus. The speed of 350mhz is easily reached by multiplying the 100mhz bus by x3.5. Unfortunately, there is no way to actually get a speed of 350mhz on the S1571. You would have to either take a loss in speed and settle for 333mhz (66 x 5), in which case you might as well buy a 333mhz model, or try to overclock it to 366mhz (66 x 5.5) and hope for the best.

K6-2/366
This processor works fine on the S1571. Just remember to set the multiplier to x5.5 (66 x 5.5 = 366). Also, you may need to enable the Write Allocate feature of the cpu (see "Note:" above).

K6-2/400
AMD decided to re-map the x2 multiplier to x6 in the K6-2 model 8/[F:8] (CXT core) and above. This allows for a processor speed of 400mhz on 66mhz bus systems (66 x 6 = 400). So, the K6-2/400 works fine in the S1571. However, you will need to enable the Write Allocate feature of the cpu (see "Note:" above).

K6-2/450 and above
The only way to get a speed of 450mhz on the S1571 would be to overclock the bus to 75mhz and setting the multiplier to x6. Unfortunately, running the bus at 75mhz brings in a lot of other problems and I do NOT recommend it (see the Overclocking section elsewhere on this page).

The 450mhz and above AMD processors will work fine on the S1571 if you simply "underclock" them. I am running a K6-2/500 set at 400mhz (66mhz bus with an x6 multiplier) on my S1571 server and it is working great.

AMD K6-III

The information presented in the above AMD K6-2 (up to 333mhz) and the AMD K6-2 (350mhz and above) sections also applies to the K6-III/400 and higher processors. However, there are some differences that need to be mentioned.

The AMD K6-III processor will work fine on the Tyan S1571 motherboard with a few setting changes and one minor drawback. Unfortunately, the same processor speed limitations that apply to the K6-2 also apply to the K6-III. So, the best processor that can currently be used with the S1571 is the K6-III/400.

First, you will need to upgrade your bios to the v1.06 bios available for download from Tyan. As with the K6-2/400, AMD re-mapped the x2 multiplier to x6 in the K6-III allowing for a processor speed of 400mhz on 66mhz bus systems.

Setting Changes
There are some system setting changes that you will need to make before the K6-III will work properly on the S1571. First, you will need to disable the "System BIOS Cacheable" option in the system BIOS. For some reason, the motherboard won't even boot unless this option is disabled. Second, you will want to enable the "Write Allocate" feature of the cpu. The updated v1.06 bios enables the Write Allocate feature on the K6-2 model 8/[7:0], but doesn't seem to enable it on the K6-2 model 8/[F:8] or the K6-III. Although the system will run fine without this option enabled, it will not perform as well as it should. The Write Allocate feature can be enabled on the K6-2 model 8/[F:8] by using either the "Setk6" program or updating to the J.2 patched bios. I have made both of these files available for download in the utility programs area of this page.

The Drawback
There is one minor drawback when using the K6-III with the S1571. The advanced "Write Combining" feature of the cpu doesn't seem to work properly. In fact, enabling this feature usually causes Windows to simply "lock-up" during start up. However, this feature results in only a small gain in performance, so it's no great loss.

AMD Mobile K6-2+/K6-III+ and "E" processors

The mobile K6-2+/K6-III+ processors have a lower core voltage that allows them to run cooler and more efficiently in laptop/notebook systems. Even though the core voltage is lower than the 2.0v capabilities of the S1571, they can still be used on this motherboard. However, you will need the new J.2 patched bios to support these processors (see the "BIOS" section of this page).

The "E" processors are "Embedded" processors. These were designed for industrial and other special applications. These may not work on the S1571. So far, I only know of 1 person who has tried the embedded processor on the S1571. The processor did NOT work on their S1571 system. If anyone has succesfully used an embedded processor on the S1571, please email me at [email protected] with any information that might be helpful.

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Tyan S1571 bios v1.06 with J.2 Patch

Support for the AMD K6-2 and K6-III Write Allocate feature
Support for the AMD K6-2+ and K6-III+ processors

(Note! The SetK6 program is no longer needed with this bios)

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Tyan S1571 Jumper Settings

CPU Multiplier Settings

BF0 BF1 BF2 x1.5 OFF OFF OFF x2 ON OFF OFF x2.5 ON ON OFF x3 OFF ON OFF x3.5 OFF OFF OFF x4 ON OFF ON x4.5 ON ON ON x5 OFF ON ON x5.5 OFF OFF ON x6* ON OFF OFF

NOTES: 1) The CPU multiplier is calculated by simply multiplying the bus speed by the multiplier. For example, an AMD K6/266 would use an x4 multiplier (66.667 x 4 = 266mhz). 2) These settings will work for most processors. However, If you are using an AMD K6/233, or any Cyrix M II, these settings will NOT work for overclocking. All 3 pins (BF0, BF1, and BF2) are on these processors, but the BF2 pin is disabled. *The x6 multiplier applies only to the K6-2 model 8/[F:8] (CXT core) and the K6-III. This does include the K6-2/400.

CPU IO Voltage Setting (something Tyan left out of the manual.)

VIO 3.5v OFF 3.3v ON

Note to S1573 users: The VIO setting on the S1573 is set with jumpers JP24, JP25, and JP26. However, the manual states that JP26 may not be present on some boards. These 3 jumpers need to be ON for a 3.3v IO, and OFF for a 3.5v IO.

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Overclocking by increasing the bus speed

This is the most dangerous way to overclock your system. I strongly urge you not to try it. Here's the problem: when you increase the bus speed, everything speeds up. This includes the PCI bus, ram access, etc. This may sound like a good idea, but you have to be REAL careful. The PCI bus specifications state that the PCI bus is supposed to be ran at 33mhz. So, PCI card companies design their products to run at 33mhz. This includes video cards, etc., AND the PCI IDE hard drive controllers built-in on the motherboard. On the S1571 the PCI bus speed is determined by dividing the bus frequency by 2. So, at 66mhz, the PCI bus will run at the proper 33mhz. If you try to run the bus at 83mhz, the PCI bus would then be running at 41.5mhz! You would have a hard time getting the system to even boot-up at this speed. Even a 75mhz bus setting will cause problems. First, your video card would most likely lock up. Then, you could start getting memory read errors and file corruptions on your hard drive. One other problem is that your chipset, ram, and PCI cards will ALL run much hotter. This is because they are running at a faster speed. I've known people who have fried their chipsets and video cards by overclocking this way. Most motherboards designed with the 100mhz front side bus set the PCI bus at a fixed 33mhz, so they work fine at the faster bus speeds. However, the S1571 isn't designed that way. Sometimes increasing the amount of ram wait states and lowering the PIO and/or UDMA mode for your hard drives in the bios will help, but not always.

Note for those using faster processors: There seems to be a new problem when you try to combine the increased speed of a new processor with the already increased speed of an overclocked bus. The errors usually come from increased "access" speeds to the ram, the on-board (L2) cache, the chipset, and the PCI bus. The increased access speeds obtained from running the bus at 75mhz are sometimes within tolerable limits with a slower processor. However, once you add the increased speed of a faster processor to the already increased bus speed, the access timings get to be too much for the system to handle. I learned this myself the hard way. I was able to run the bus at 75mhz with my K6-233, overclocking it to 266mhz. However, once I upgraded to the K6-2/333, I could no longer get away with the 75mhz bus speed. I started getting ram errors, random re-starts, disk errors, etc. Many people have emailed me who have found the same to be true on their systems. So, increasing the bus speed almost never works with a faster processor... at least not on the Tyan S1571.

Overclocking by changing the CPU multiplier

This is by far the safest way to overclock your system. Setting the CPU multiplier to a higher setting only changes the speed of the processor, so the bus speed is left at the proper 66mhz setting. I've been running my AMD K6-2/333 at 366mhz this way without trouble. The most common problems to watch out for with this method are random system lock-ups, unexpected program crashes, and other odd system behavior.

Note: Trying to overclock the AMD K6/233 processor (and lower) by changing the CPU multiplier to a higher setting will NOT work. All 3 pins (BF0, BF1, and BF2)are on the K6/233, but BF2 is either internally pulled high, or disabled in some way. I found this out the hard way with my own K6/233 and in some obscure little side note in the AMD K6 documentation. This might have been their way of preventing overclocking.

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73JSP106.ZIP

Support for the AMD K6-2 and K6-III Write Allocate feature
Support for the AMD K6-2+ and K6-III+ processors

(Note! The SetK6 program is no longer needed with this bios)