Maybe you've set multiplier of 1.5 which is interpreted by MMX CPUs as 3.5 multi and the FSB is set for the "weird" frequency of 55 MHz (supported by some s.7 chipsets), resulting in 3.5 multi x 55 MHz FSB = 193 MHz CPU.

Yes this does seem to be the case as it does have a 55mhz clock setting. I've tried to set it to 66mhz but it just won't move it's completely stuck so i guess this will have to do.

It now plays Jazz Jackrabbit 2 at 640x480 smoothly which was my aim so this will suffice. If anything i aim to make the machine slower now for DOS games so Jazz2 was the peak of what i needed performance wise

Anything above these requirements are why i have my second windows 98 rig.

Just replace the broken DIP switch and set correct CPU frequency by 3 multi x 66 MHz FSB.

Hi Crinaleo,

What happened to this motherboard? It looks like it is caked in some sticky dust. That’s probably why the dip-switches got stuck. Perhaps cleaning the dip-switched with a non-aggressive solvent, like isopropyl alcohol, will get them going.

Anyway, here are some details about the FSB and Multiplier settings on this SY-5VD board.
Looking at the manual from https://theretroweb.com/motherboards/s/soyo-sy-5vd is see that SW1/1 and SW1/2 set the Multiplier and SW1/3, SW1/4, and SW1/5 select the FSB.
Here are the tables:

Multiplier:
x1.5: SW1/1-Off; SW1/2-Off
x2.0: SW1/1-On; SW1/2-Off
x2.5: SW1/1-On; SW1/2-On
x3.0: SW1/1-Off; SW1/2-On
x3.5: SW1/1-Off; SW1/2-Off
Note that the x1.5 and x3.5 settings are the same. You get x1.5 only on the Pentium and K5. All other CPUs, like Pentium MMX and K6 work as x3.5 with this setting.

Bus Clock (FSB):
50MHz: SW1/3-On; SW1/4-On; SW1/5-Off
55MHz: SW1/3-On; SW1/4-Off; SW1/5-On
60MHz: SW1/3-On; SW1/4-Off; SW1/5-Off
66MHz: SW1/3-Off; SW1/4-On; SW1/5-Off
75MHz: SW1/3-Off; SW1/4-On; SW1/5-On

Your Pentium 166 and Pentium 200 MMX both use a 66MHz FSB, so changing SW1/3, SW1/4, and SW1/5 was not needed and you only had to set DIP-switch SW1/1 from On to Off to change the Multiplier from x2.5 to x3 to get the CPU Speed to 200MHz. 😉

The SW1 setting that gave you 100MHz on the Pentium and 233MHz on the MMX is easy to explain with the above tables. You had an 1.5 x 66MHz setting there, that worked as 3.5 x 66 on the MMX.

I agree with analog_programmer that the later 192.5MHz setting you got on the MMX can only be explained by 3.5x 55MHz. However, this low FSB will hurt performance and 3.0 x 66MHz is better. 😀
I hope you can get the DIP-switches going again.

Now about the indications from my CPU Identification utility, the “Time Stamp Counter” text is to inform you it is using the most accurate method to measure the Internal CPU Speed. This program has two ways to measure the CPU Speed and when you don’t see te TSC message, you know that the less accurate instruction timing method was used.
The 3 dashes behind the Clock Multiplier mean that this CPU does not report its Multiplier through software. Therefore the program can’t tell you what it is.
This CHKCPU tool comes with a CHKCPU.TXT file that explains these indications in detail. 😉

Cheers, Jan

analog_programmer wrote on 2024-08-24, 18:22:

Maybe you've set multiplier of 1.5 which is interpreted by MMX CPUs as 3.5 multi and the FSB is set for the "weird" frequency of 55 MHz (supported by some s.7 chipsets), resulting in 3.5 multi x 55 MHz FSB = 193 MHz CPU.

Anyway, here are some details about the FSB and Multiplier settings on this SY-5VD board. Looking at the manual from https://the […]
Show full quote

Anyway, here are some details about the FSB and Multiplier settings on this SY-5VD board.
Looking at the manual from https://theretroweb.com/motherboards/s/soyo-sy-5vd is see that SW1/1 and SW1/2 set the Multiplier and SW1/3, SW1/4, and SW1/5 select the FSB.
Here are the tables:

Multiplier:
x1.5: SW1/1-Off; SW1/2-Off
x2.0: SW1/1-On; SW1/2-Off
x2.5: SW1/1-On; SW1/2-On
x3.0: SW1/1-Off; SW1/2-On
x3.5: SW1/1-Off; SW1/2-Off
Note that the x1.5 and x3.5 settings are the same. You get x1.5 only on the Pentium and K5. All other CPUs, like Pentium MMX and K6 work as x3.5 with this setting.

Bus Clock (FSB):
50MHz: SW1/3-On; SW1/4-On; SW1/5-Off
55MHz: SW1/3-On; SW1/4-Off; SW1/5-On
60MHz: SW1/3-On; SW1/4-Off; SW1/5-Off
66MHz: SW1/3-Off; SW1/4-On; SW1/5-Off
75MHz: SW1/3-Off; SW1/4-On; SW1/5-On

Your Pentium 166 and Pentium 200 MMX both use a 66MHz FSB, so changing SW1/3, SW1/4, and SW1/5 was not needed and you only had to set DIP-switch SW1/1 from On to Off to change the Multiplier from x2.5 to x3 to get the CPU Speed to 200MHz. 😉

The SW1 setting that gave you 100MHz on the Pentium and 233MHz on the MMX is easy to explain with the above tables. You had an 1.5 x 66MHz setting there, that worked as 3.5 x 66 on the MMX.

I agree with analog_programmer that the later 192.5MHz setting you got on the MMX can only be explained by 3.5x 55MHz. However, this low FSB will hurt performance and 3.0 x 66MHz is better. 😀
I hope you can get the DIP-switches going again.

Chkcpu & analogue programmer, THANK YOU!

This got me thinking i wondered what the 55Mhz settings were and turns out it was the inverse of what setting i have made as per the manual.

Turns out, these are printed in error and i tried inverting these settings for the sake of it and...

Amazing! So yeah, turns out i had managed to set them correctly but the manual is actually incorrect (or hell maybe the printed "ON" location on my drip switch is incorrect) who knows but thankfully now its all setup correctly as it should be.

Even all the multiplier info is showing up now and im getting 66Mhz FSB which has actually had a pretty big effect on performance. PlayerBench score went from 18.1 to 20.4 & 143 to 149 on processor benchmark.

If it wasn't for that post i wouldn't of bothered to check - thank you again!

What happened to this motherboard? It looks like it is caked in some sticky dust. That’s probably why the dip-switches got stuck. Perhaps cleaning the dip-switched with a non-aggressive solvent, like isopropyl alcohol, will get them going.

Its an ex warehouse machine so yeah... it's pretty filthy it could use a good soak to be honest but it works and i've cleaned it significantly since i got it haha these machines are so expensive over here and this was cheap so a new PSU later and some cleaning and it's going to be a great DOS machine 😁