Seeing you have the hardware, running a benchmark should quickly give you the answer. But I doubt it will work seeing the manual specifically mentions this. I guess they put headers on the board so you don't have any loose cables flying around 🤣

Also the LED readings on the case are not "measured" at all. You will find a set of jumpers behind the LEDs, allowing you to set the readout. E.g. you can set the jumpers to display HI and LO or whatever other numbers you like.

On Pentium Boards usually the FSB is switched between 66 MHz and 50 MHz.

If there is a proprietary connector, maybe it'll disable the internal cache.

Isn't the connector just for the led, to always show that the system is in turbo mode, regardless whether the turbo button is pressed or not?

Usually there are two connectors labelled TB/LED and TB/SW. LED and Switch...

Not on Pentium mainboards. [at least I've seen a few with turbo LED only]

There are some Pentium motherboards that support the switch. For example on the Tyan S1462 (430NX) it disables the cache:

Tyan S1462 manual wrote:

3.10 Turbo Switch J16 Most case's panel has a turbo switch to control system speed. Slower execution speed is required for the […]
Show full quote

3.10 Turbo Switch J16
Most case's panel has a turbo switch to control system speed. Slower
execution speed is required for the programs developed for the old XT.
Because Pentium cannot slow its clock speed on the fly, S1462 uses simu-
lation method to implement TURBO switching function. The J12 on the
mainboard should be connected to the TURBO switch on case panel.

The Gigabyte GA-586ID (another 430NX based moterboard) manual states:

Gigabyte GA-586ID manual wrote:

3.10 TURBO SWITCH CONNECTOR INSTALLATION The TURBO switch on the panel is used for controlling the system speed. Some program de […]
Show full quote

3.10 TURBO SWITCH CONNECTOR INSTALLATION
The TURBO switch on the panel is used for controlling the system speed. Some
program developed on XT should be executed with a low speed system, so a
high speed system needs the speed switching function to change its running
speed.
Because a PENTIUM cannot accept real clock speed change when program is
executed, so the mainboard uses simulation method to implement TURBO
switching function. The J3 on mainboard should be connected to the TURBO
switch on panel, and user can push in or pop out the TURBO switch to enable or
disable the turbo function of system.

I haven't seen a Triton (any version FX/HX) motherboard with Turbo switch capabilities, only 'always on' turbo LEDs. If you really want turbo with Pentium look for early Mercury (430LX) or Neptune (430NX) motherboards, but check the manual before buying any.

Well see this:
http://mail.lipsia.de/~enigma/neu/pics/VXPro.jpg
Upper left corner: TB-LED and TB-SW

or this one:
http://mail.lipsia.de/~enigma/neu/pics/gigabyte_ga586hx2.jpg
Upper left corner, TB and TD (Switch and Led)

Event the Tyan S1563D which is a Dual Pentium Board based on the 430HX has a Turbo Switch (J26).

and this HX mainboard, with the I/O Pin Layout printed in the center of the mainboard:
http://mail.lipsia.de/~enigma/neu/pics/mainboard_i430HX.jpg

In one thing you are right - the 430HX has no de-turbo functionality in the chipset itself and this is why usually the FSB or maybe Cache is switched. Though I never had a S7 board that switches Cache with the Turbo Switch.

This SIS5591 mainboard has also a turbo switch (upper left corner of the image)
http://mail.lipsia.de/~enigma/neu/pics/ga586sg.jpg

A TX Board example with TB Switch:
http://mail.lipsia.de/~enigma/neu/pics/mainbo … d_ga_586tx3.jpg

I would break it down more or less to the following rule:
If the board is AT then a Turbo Switch is likely there.
If the board is ATX then it is probably not there.

I have a Pentium motherboard with turbo switch headers. I'll post the recent findings I had with it soon.

wow, thanks for all the replies. Yeah, my board is the Tyan S1563, but I'm only running one processor. The board has both turbo switch and led headers. (wish I could skip the memory count test)

At any rate, the turbo button definitely doesn't look to be too effective. I'm trying to build a vintage gaming system, and while I wait to find a good 486 board with PCI slots and PS2 support I was hoping to use this board in the meantime... but it looks to be difficult.

What you mean exactly by 'difficult'?
For slowing it down?

On pentium 1 boards you can switch the cache on demand using a simple commandline program. I use usually cpucache.com.
So you have cache switching and turbo switching and additionally the option to use a slowdown utility or throttle.
I think thats quite versatile compared to other solutions.

Though if you want real comfort use a K6-2+ or a K6-III+, where you can change the multiplicator and cache from the commandline.

elianda wrote:

What you mean exactly by 'difficult'? For slowing it down? […]
Show full quote

What you mean exactly by 'difficult'?
For slowing it down?

On pentium 1 boards you can switch the cache on demand using a simple commandline program. I use usually cpucache.com.
So you have cache switching and turbo switching and additionally the option to use a slowdown utility or throttle.
I think thats quite versatile compared to other solutions.

Though if you want real comfort use a K6-2+ or a K6-III+, where you can change the multiplicator and cache from the commandline.

I mean difficult to use as a headache-free replacement for a 486 system. It's also slow to boot because it has to go through and count the memory (no way to disable it in BIOS). I could use one of the programs for disabling cache, though. I just kind of feel like I want an original system for the era.

I do have a K6-2+, as well as a ton of pentiums, pentium ii and iii, and Athlon stuff. I'm actually planning on building 4-5 different vintage systems (386, 486, Pentium Pro, Pentium III, etc). The 486 is the most crucial, I think, because that was the one I was planning on putting my Roland LAPC-I into. I want it to play every game that supports Roland flawlessly. For ultimate compatibility with speed sensitive games I may build a 386, but I'm probably only going to have an old MediaVision Thunderboard in it.

Interesting...

To be honest the Roland LAPC-I would be better suited for the 386 and for the 486 you want to have a Roland General Midi module.

Most games supporting MT-32 run beautifully on a 386. General Midi was the go on 486 and Pentium era games. However there are a few exceptions such as Strike Commander which really needs a 486DX-2 and also support MT32. I don't know if this game supports General Midi, but other Games such as Privateer also support General Midi.

Wing Commander will definitely run too fast on a 486. Unpatched Sierra adventures will have timing bugs (this is well documented and there are patches for the Space and Kings Quest Collections). In many games you will find the scrolling to be too fast (e.g. Space Quest 4).

Still a 486 can be slowed down (Turbo, Cache setting) to reach 386 speeds, so it might not be necessary to build a 386 after all.

So basically your approach to having several machines is on the right track 😀 However you might find an external MT-32 easier as you could use it with several computers. You could sell your LAPC-I and easily get a MT-32, a SC-55 and a few MPU401 adapters...

Most later DOS games run fine on any machine. In this case a Slot 1 Pentium 3 is the way to go, especially with SVGA games. Now there might be games that don't run on a Pentium 3 and run too slow on a 486 but I'm not sure about that...

With my latest socket 5 P133 trial, I'm able to get multiple speed configurations :

1. A Pentium 133 (good for those games which displayed "runs well on pentium, or Recommended : Pentium" labels),

2. A 486DX2-66 with the Turbo button off

3. A 12-MHz 286 with the internal cache disabled through command line utility, and

4. An 8-MHz XT/AT with both the turbo mode and internal cache disabled.

The speeds are good translations of the said systems, and since they are slowed down in hardware mode, the resultant speed is consistent.

So far, I've noticed that upto the Pentium 133MHz, the Sierra games run well without the timing bug patches, and there are no audio hardware initialization error messages. On the other hand, a P166, MMX or not, produce the error message and required to run the timing patch. So I guess, a 486 may not need the patches, even when turbo mode is on.

Of course, doing the hardware way is much tedious, but it's why we're all here anyway. 😀

Whenever we get frustrated, we can rest easy that there's always dosbox to ease the tension when emulating multiple old machines. 😎

Mau1wurf1977 wrote:

Most later DOS games run fine on any machine. In this case a Slot 1 Pentium 3 is the way to go, especially with SVGA games. Now there might be games that don't run on a Pentium 3 and run too slow on a 486 but I'm not sure about that...

There are some games that require something in between a typical 486 and a P3. Magic Carpet (SVGA), Witchhaven 2 (SVGA; the jumping is strange), Azrael's Tear, and I know there are others. One solution would be to remove the P3 CPU cartridge, and replace it with a "slow" P2 or celeron, or an underclocked P2, but chaning a slot 1 cartridge can be a nuisance.

I think Magic Carpet's SVGA sweet spot is either 133 or 166 MHz. I can't remember which. That game might be a bit awkward to play perfectly on a slot 1 system. I guess the way to solve that is to crank up the speed on the 486 system! 😀 Malik's impressive "turbo button powered" socket 5 P133 sounds really good. 😎