To be honest, you'll need to mostly test software yourself. Depending on the BIOS, a lot of the cache-disabling tools may not even work. On one HP Vectra, almost no tools worked, on my new HP Vectra (slightly newer model), Setmul works great.

I'd steer clear of software that uses tricks to slow down games like Mo'slo. I never liked it - while it does slow down a game, it comes at a serious price: your frame rate tanks and there's massive input lag. Games that rely on speed and reflexes are NOT going to like Mo'Slo. For certain adventure games and strategy games that require no fast reactions ... sure, it works. But even then I find that it's not very smooth and responsive.

Just stick to programs that disable cache. It works really well and will turn even a Pentium into a 286-386.

This video from Phil is a very good resource on slowing down Pentium MMX to play old DOS games.

https://youtu.be/xcBmEjXg2ME

Sorry I didn't get to this last weekend. I just tried Setmul on the 200MHz MMX and with the External Cache turned off through BIOS, the lowest 3dBench2 score I could get was 17. Still too fast for Wing Commander. Phil says around 9.8 is ideal for that game, but I just can't get it that low and it still plays really fast.

Besides getting a slower MMX or whatever processor I'm back to the drawing board. I also don't like how I have to go into the BIOS to manually turn the cache off – that's not something the kids can do (or that I trust them to do 😉 and that also leaves out things like changing the FSB jumpers on the MB.

I'm going to try the 100mhz next. If I can use that FastVid program to get decent frame rates in Quake (fastvid doesn't seem to work on the 200MMX...), AND it'll let me slow it down enough for these earlier games with Setmul (moreso than what the 200MMX can do), that would be PERFECT.

Some notes about my BIOS Caches if I'm doing something wrong: There seems to only be two options for cache in the BIOS: Internal and External. When I turn Int off, Ext gets grayed out. Int and Ext on 3dBench2 is 115.6. Int on, Ext off = 114.2. With both caches on, Setmul set to "Slowest" I get 32. With Int off (which turns off Ext too I think as it gets grayed out automatically), Slowest = 17

Still looking for answers about the case swap and turbo questions as well. The 200MHZ system w/ M575 Socket 7 MB doesn't seem to have a turbo jumper/wire anywhere on it, so I don't know why it's in the case with the Turbo button. The DX4 100MHz is in the case with NO turbo, but the M919 motherboard DOES have a place to put a turbo button onto... but I just can't find out how Turbo works overall. Like do ALL motherboards of this era and ALL processors of this era work with Turbo on and off? Or even if my MB has the connector for it, but the CPU itself isn't compatible with this feature, it still wouldn't work then? It's a TON of work to swap two MB's into each others case (which I've never done before...) which is why I'm trying to find this out BEFORE I go this route...

...It also doesn't help that I don't even know what exactly the turbo button on or off does. Like does it cut the voltage to slow down or speed up? Is the CPU speed cut in half, or by a third, or a certain multiplier or what? Or does it disable certain cache(s) when it's turned on or off? Any help in learning this is appreciated (searching for "turbo button" doesn't tell me this info, or I've failed at finding something I understand).

Nice computers.

Using the "Turbo" button and "Setmul" ( Set multiplier ) utility I can slow down my 486dx4-100 computer to a 286@10mhz. and it runs fine.

My build:
486 Multimedia dream build ( 1993/94 )

I would leave the Pentium 200mhz build alone.

Mosts stuff will run on the 486dx4-100 or at 286@10mhz.

See this posts:
Re: 486 Multimedia dream build ( 1993/94 )

Intel486dx33 wrote on 2020-03-21, 19:08:

Using the "Turbo" button and "Setmul" ( Set multiplier ) utility I can slow down my 486dx4-100 computer to a 286@10mhz. and it […]
Show full quote

Using the "Turbo" button and "Setmul" ( Set multiplier ) utility I can slow down my 486dx4-100 computer to a 286@10mhz. and it runs fine.

My build:
486 Multimedia dream build ( 1993/94 )

I would leave the Pentium 200mhz build alone.

Mosts stuff will run on the 486dx4-100 or at 286@10mhz.

Thanks. I will give the 100MHz a whirl!

Can you tell me what exactly the Turbo button does? I can't even find such basic information about this, and I think this is my 4th post asking for any kind soul to chime in 🤣. I've googled a ton and it's always generic info like turbo button/mode "increase or decrease performance", or is a "normal or an enhanced turbo speed" (while others say turbo actually slows down...), or it "increased the clock frequency on the processor" ...but NOTHING about what's needed compatibility wise to make this work...

...like can ALL processors use this (remembering that there was quite a few DX4 100MHz models made)? Can ALL motherboards of this era use turbo (which my 200mhz seems to not have this...). Just SUPER basic things like that I would need to know before I get into switching cases to have a turbo button for the 100MHz (which would be a BIG job for me).... and then it brings me back to the same question again about how I don't know if the 100mhz's CPU and MB and Case would all be compatible with a Turbo feature to begin with... because I don't know if the Turbo button works on a multiplier basis or what... and aren't some chips NOT multiplier unlocked and wouldn't work with this feature if that is the case? Going in circles here and grasping at straws... but just trying to figure out the basics before I get into a larger project!

I'm going to put the SB card back into the 100MHz and run those 3DBench2 tests and see what happens with the numbers... but would LOVE to do this proper and switch cases and use turbo if it'll help me play some of these very early games at their correct speed.... then that brings me to possible BIOS settings I might have to use (assuming in conjunction with SetMul? - I needed to change BIOS settings on the 200MHz so SetMul wasn't able to switch all these on/off on the fly I don't think, HAD to go into the BIOS which was a bummer form a usability standpoint) – the 100MHZ's BIOS has several features I don't know what they do:

This one is simple, and probably works the same way as the AMIBIOS the 200MHz has - where I can turn off External cache on/off, but if I turn off Internal cache the external automatically gets grayed out in the BIOS

I don't think the 200MHz had this 'L2 Cache mode' option? (I think this is one which SetMul was turning off)

Cache speed options 2-2-2?

I'll have to go back in and make sure there wasn't any I'm missing. I didn't see the L1 cache there, but I think the External/Internal cache option is the L1.

Dochartaigh wrote on 2020-03-22, 18:50:

Thanks. I will give the 100MHz a whirl! […]
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Thanks. I will give the 100MHz a whirl!

Can you tell me what exactly the Turbo button does? I can't even find such basic information about this, and I think this is my 4th post asking for any kind soul to chime in 🤣. I've googled a ton and it's always generic info like turbo button/mode "increase or decrease performance", or is a "normal or an enhanced turbo speed" (while others say turbo actually slows down...), or it "increased the clock frequency on the processor" ...but NOTHING about what's needed compatibility wise to make this work...

...like can ALL processors use this (remembering that there was quite a few DX4 100MHz models made)? Can ALL motherboards of this era use turbo (which my 200mhz seems to not have this...). Just SUPER basic things like that I would need to know before I get into switching cases to have a turbo button for the 100MHz (which would be a BIG job for me).... and then it brings me back to the same question again about how I don't know if the 100mhz's CPU and MB and Case would all be compatible with a Turbo feature to begin with... because I don't know if the Turbo button works on a multiplier basis or what... and aren't some chips NOT multiplier unlocked and wouldn't work with this feature if that is the case? Going in circles here and grasping at straws... but just trying to figure out the basics before I get into a larger project!

I'm going to put the SB card back into the 100MHz and run those 3DBench2 tests and see what happens with the numbers... but would LOVE to do this proper and switch cases and use turbo if it'll help me play some of these very early games at their correct speed.... then that brings me to possible BIOS settings I might have to use (assuming in conjunction with SetMul? - I needed to change BIOS settings on the 200MHz so SetMul wasn't able to switch all these on/off on the fly I don't think, HAD to go into the BIOS which was a bummer form a usability standpoint) – the 100MHZ's BIOS has several features I don't know what they do:

This one is simple, and probably works the same way as the AMIBIOS the 200MHz has - where I can turn off External cache on/off, but if I turn off Internal cache the external automatically gets grayed out in the BIOS

I don't think the 200MHz had this 'L2 Cache mode' option? (I think this is one which SetMul was turning off)

Cache speed options 2-2-2?

I'll have to go back in and make sure there wasn't any I'm missing. I didn't see the L1 cache there, but I think the External/Internal cache option is the L1.

Hello,

You wrote very much, I am afraid, I skipped large parts of it. 😁
So I am referring to the 486 machine only.
About Turbo: On 386 machines, it really switched the external clock on the mainboard, for example from 33MHz to 25MHz.
With 486 that's technically not possible.
So the NO-turbo setting on 486er can't touch the external clock (33MHz for a DX4/100), so it slows down using other mechanisms.
As far as I know it is similar to disable L1 cache. Disabling L1 cache somehow extremely cripples the performance of a 486 machine. So without L1 cache you are in terms of performance BELOW a 386.

But you can test it by yourself:
1) Configure optimal settings and disable Turbo (via jumper on the mainboard) and run a benchmark.
2) Use same BIOS configuration, but disable L1 cache (= internal cache, L2 cache does not matter with L1 disabled) and run a benchmark.
I guess it is in the same range.

CoffeeOne wrote on 2020-03-22, 19:21:

But you can test it by yourself: 1) Configure optimal settings and disable Turbo (via jumper on the mainboard) and run a benchm […]
Show full quote

But you can test it by yourself:
1) Configure optimal settings and disable Turbo (via jumper on the mainboard) and run a benchmark.
2) Use same BIOS configuration, but disable L1 cache (= internal cache, L2 cache does not matter with L1 disabled) and run a benchmark.
I guess it is in the same range.

To turn turbo on (which I assume slows down the computer), is it as simple as using a jumper on it so those two pins are bridged? So I can do that without having a physical turbo button in the case? (which the 100MHz doesn't have a button on the case for Turbo). If so I'll give that a try and see what happens - thanks.

Dochartaigh wrote on 2020-03-22, 19:26:

CoffeeOne wrote on 2020-03-22, 19:21:

But you can test it by yourself: 1) Configure optimal settings and disable Turbo (via jumper on the mainboard) and run a benchm […]
Show full quote

But you can test it by yourself:
1) Configure optimal settings and disable Turbo (via jumper on the mainboard) and run a benchmark.
2) Use same BIOS configuration, but disable L1 cache (= internal cache, L2 cache does not matter with L1 disabled) and run a benchmark.
I guess it is in the same range.

To turn turbo on (which I assume slows down the computer), is it as simple as using a jumper on it so those two pins are bridged? So I can do that without having a physical turbo button in the case? (which the 100MHz doesn't have a button on the case for Turbo). If so I'll give that a try and see what happens - thanks.

Yes, if you have a turbo switch on the case, then use it of course!
EDIT: Sorry misread, you don't have a turbo switch on the case.
Turbo on is closed (on all mainboards that I know).
Turbo on means FAST of course.
Turbo off is for slowing down.

Here's a complete breakdown of slowdown options for my 486 DX2/66 and Pentium 200MMX. This should give you an idea of what your systems might be capable of. Although, each 486 motherboard's Turbo performance is a bit different, so your mileage may vary.

CoffeeOne wrote on 2020-03-22, 19:31:

Turbo on means FAST of course.
Turbo off is for slowing down.

I've been reading people argue this point on quite a few posts. Seems like for some people that depends on the case and/or MB combo as Turbo on (contrary to what that logically means) seems to slow down some peoples computers...which likewise makes no sense to me 🤣. I've been curious what mine will be (if I choose to swap cases that is...).

clueless1 wrote on 2020-03-22, 19:32:

Here's a complete breakdown of slowdown options for my 486 DX2/66 and Pentium 200MMX. This should give you an idea of what your systems might be capable of. Although, each 486 motherboard's Turbo performance is a bit different, so your mileage may vary.
time machine.PNG

Is there a legend for what all those acronyms stand for? DCD, VPD, L1D, etc.? Is that terminology from SetMul or like industry-standard acronyms I should learn?

I'm unable to get my 200 MMX down to any of your numbers below 17 – numbers where it says L1D, L1D+BPD, L1D+BPD+VPD. So it very well could be because of my MB doesn't have those Cache options or whatnot (seems to only have External and Internal and that's it).

Dochartaigh wrote on 2020-03-22, 20:33:

Is there a legend for what all those acronyms stand for? DCD, VPD, L1D, etc.? Is that terminology from SetMul or like industry-standard acronyms I should learn?

It's all in the setmul documentation. L1D is L1 cache disable (could be done either through the BIOS or with setmul). The "test register" TR12 options are available on MMX cpus only. If you haven't tried them on your MMX, give 'em a shot. Quoted the relevant parts below:

PARAMETERS /? - default help screen. [Multiplier] - as a single digit like '5', or '5.0', or halves like '5.5'. L1D - L1 Cache D […]
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PARAMETERS
/? - default help screen.
[Multiplier] - as a single digit like '5', or '5.0', or halves like '5.5'.
L1D - L1 Cache Disable.
L1E - L1 Cache Enable.
L1DX - L1 Cache Disable, exclusively, leaves L2 untouched, for K6-2+/III+.
L1EX - L1 Cache Enable, exclusively, leaves L2 untouched, for K6-2+/III+.
L2D - L2 Cache Disable, but cannot toggle any motherboard L2/L3 cache.
L2E - L2 Cache Enable, but cannot toggle any motherboard L2/L3 cache.
ICD - L1 I-Cache Disable, on VIA C3 or Winchip.
ICE - L1 I-Cache Enable, on VIA C3 or Winchip.
BPD - Branch Prediction Disable, on VIA C3.
BPE - Branch Prediction Enable, on VIA C3.
INFO - Show PowerNow! info of AMD K7 or K8.
CMD - Disable clock speed measurement.

Pentium P54C and MMX test register "TR12" options. Parameters:
BPD - Disable Branch Prediction.
VPD - Disable V Pipeline.
L1DX - Disable L1 cache exclusively.
CCD - Disable L1 code cache.
DCD - Disable L1 data cache.
PFE - Pentium Features Enable; Resets the above TR12 options to default.
The status of register TR12 cannnot be read by design.

Dochartaigh wrote on 2020-03-22, 20:33:

I'm unable to get my 200 MMX down to any of your numbers below 17 – numbers where it says L1D, L1D+BPD, L1D+BPD+VPD. So it very well could be because of my MB doesn't have those Cache options or whatnot (seems to only have External and Internal and that's it).

My MMX system does not have L2 cache on the motherboard, so my results are naturally a little slower, but yours may be able to be disabled through the BIOS or with setmul, which should get your speeds down a bit more. Just try those setmul TR12 parameters (regardless of whether your motherboard has L2 or not) and see what happens.

clueless1 wrote on 2020-03-22, 20:47:

My MMX system does not have L2 cache on the motherboard, so my results are naturally a little slower, but yours may be able to be disabled through the BIOS or with setmul, which should get your speeds down a bit more. Just try those setmul TR12 parameters (regardless of whether your motherboard has L2 or not) and see what happens.

Hey thanks a bunch! I've been using Phil's Computer Lab's presets (like "slow" "slowest", etc.) for SetMul, and those may very well NOT have the MMX specific parameters like TR12 in it - I'll give it a try before I give up on the 200 MHz (as I would MUCH rather have the 200 for games like Quake...and if it can be made just a bit slower it might work for all those other old DOS games too).