I can second what @RaiderOfLostVoodoo said regarding this forum.
Btw, @Stiletto did a great collection, found this very useful collection page when looking for slow down utilities.

RaiderOfLostVoodoo wrote on 2021-11-04, 17:59:

But I want it as a DIP switch on the front. And only for the turbo settings.
I did wonder if there is a plug and play solution. [...] So it's DIY time.

Apropos DIY...
This is a 5.25" turbo wheel with nn.n MHz display which plugs into the crystal oscillator socket.
Range is 2-33.3 MHz.
Only works with AMD processor because Intel CPUs hang when clocked below ~16MHz.

My ga-5aa has a turbo led and switch. When I push it, the light turns on, then off when button released. I guess turbo buttons had a locking feature?

retardware wrote on 2021-11-05, 02:43:

Btw, @Stiletto did a great collection, found this very useful collection page when looking for slow down utilities.

Thanks! It's pretty old (I originally posted it in 2002, updated the links in 2012!) but still perfectly serviceable! Might be missing some newer utility, IDK.
And as the sierrahelp.com page states, it's still on VOGONS!

List of Slowdown Utilities / List of Slowdown Utilities (Beta)

Some of the links may have broken again, I'll try to find the time to check it out!

The clock generator on my ASUS PVI-486SP3 changes FSB frequency that slow so that I can abuse it to switch between 40 and 25 MHz just with a 3 pin turbo switch.
However, it has a regular turbo switch connector too.

retardware wrote on 2021-11-05, 02:43:

Apropos DIY... This is a 5.25" turbo wheel with nn.n MHz display which plugs into the crystal oscillator socket. Range is 2-33.3 […]
Show full quote

Apropos DIY...
This is a 5.25" turbo wheel with nn.n MHz display which plugs into the crystal oscillator socket.
Range is 2-33.3 MHz.
Only works with AMD processor because Intel CPUs hang when clocked below ~16MHz.

A long time ago I got caught up in the idea of somehow designing a variable deturbo that could be soldered into a motherboard. I bought a few Cypress oscillator chips that were programmable, and even found the obscure programmer on eBay at one point and bought that too. Then I started fiddling with the software, realized I didn't know what I was doing and lost interest, never touching it again.

This picture is what I thought I was trying to achieve back then, complete with the rotary dial. Looks awesome.

RaiderOfLostVoodoo wrote on 2021-11-04, 17:59:

I had exactly the same idea. But I want it as a DIP switch on the front. And only for the turbo settings. I did wonder if there […]
Show full quote

j^aws wrote on 2015-02-15, 19:05:

Yes, definitely cumbersome with changing jumpers. However, I have plans to build an external jumper switch-box for all controllable jumpers (audio/ video/ motherboard) when everything is finalised, hopefully. Otherwise, I personally wouldn't bother to open the case to change jumpers.

I had exactly the same idea. But I want it as a DIP switch on the front. And only for the turbo settings.
I did wonder if there is a plug and play solution. But guess there isn't. So it's DIY time.
Did you finish it? I'm curious and would like to see the result.

Hmm, I remember this post. This idea was for my AT beige cases, and having an external switch box that I could move around between them, and not having to modify the cases. The plan was to standardise internal wiring in the cases, then using something like a DB25 connector, hook up the external switch box.

The DIP switch idea is also great and did cross my mind as well. It's discrete, too.

My original plan took a back burner as I converted a modern ATX case to AT format instead. This case also has an external flap that hides four 5 1/4 drive bays, and I'm prepared to modify the case, and use the drive bay fascia to house some funky toggle switches. They'd be discrete behind the case flap. I have all the parts - just need to finish the project.

PS: I'm amazed a six year old post reply still managed to send me an email notification!

On my 486 board (FIC 486-VIP-IO) the turbo function does nothing. The switch makes the turbo LED go on and off, but that's it. There's an option "Boot up system speed high/low" in the BIOS, it also makes the turbo LED go on/off, but does nothing either. No difference in any of the CPU/memory benchmarks. I reset the bus speed to the default 33.3 MHz in case it only works with that, but no. I'm using a Cyrix CPU - could it be that it's trying to manipulate CPU registers to enable or disable the cache and this only works on Intel CPUs? This is the only CPU I have at the moment, so I can't test it.