Are you sure your 486DX-33's BIOS doesn't provide turbo support from the keyboard? Control-Alt-Minus and Control-Alt-Plus?

You're likely to get hooked and end up building a 286 anyway 😁

Next step is to find a nice lil 286 computer at 12-16MHz :p

Personally I think the turbo button is overrated. It sure works to slow down the system pretty well and you might get to 286 speed grade. You can also loosen ram timings, disable cache L1 and L2 seperately, lower the fsb and find yourself having more control over the speed actually.

If you want a turbo button get the cheapest one and mount it in the back of your case in a slot cover or where you can put a serial port. Alternatively you may drill a hole thru a 5,25" cover and put it there for easy access.

So if you really really really want to: go ahead and get yourself a (probably expensive) case with turbo, or be patient enough to wait (probably long) until you can get one for a low price.

jakethompson1 wrote on 2022-07-03, 18:57:

Are you sure your 486DX-33's BIOS doesn't provide turbo support from the keyboard? Control-Alt-Minus and Control-Alt-Plus?

You're likely to get hooked and end up building a 286 anyway 😁

I actually don't have a 486 system yet, but I'm beginning to find parts to put one together. I wasn't aware of the possible keyboard shortcut, good to know. One of the many things I've yet to learn about the pre Pentium era of PCs. And yeah you're right, I can almost guarantee once I get a couple of 486 systems built, I'll be looking to add more (older) systems. It's the nature of this hobby and my impulsiveness.

waterbeesje wrote on 2022-07-03, 19:15:

So if you really really really want to: go ahead and get yourself a (probably expensive) case with turbo, or be patient enough to wait (probably long) until you can get one for a low price.

Yeah that's where I'm going with this, I'm not keen on paying exorbitant prices for these things, so if having a case with a turbo button is trivial, I'll stop thinking about it and just scoop something up if/when I find a good deal. Plus as you stated there are options for adding a button for this purpose.

From time to time, you'll find old AT cases on Amibay. More often than not, there will be something with a turbo button. Not sure what your price range is though, they mostly get sold from Eastern Europe, so depending where you are, shipping may be crippling. I usually buy 3 or 4 at a time (got as many as I can use now), to make shipping per case less scary 😀

You can always put a turbo switch on the rear of the case. Drill a hole in either the case or a blank slot bracket and install a panel mount switch. Wire it up to the motherboard turbo pins.

Having the turbo button is much more important than actually using it.
Somebody needs to convert their turbo button to actually live up to its name. De-Turbo should be the rated system speed, and pressing TURBO should activate water cooling, powerful (and loud) exhaust fans and overclock the shit out of your CPU.

waterbeesje wrote on 2022-07-03, 19:15:

If you want a turbo button get the cheapest one and mount it in the back of your case in a slot cover or where you can put a serial port.

I did this with one of those lamp white push switches screwed into an I/O plate with a circular hole (probably from one of those old Bus Mouse interfaces.)

Anonymous Coward wrote on 2022-07-03, 23:43:

Having the turbo button is much more important than actually using it.
Somebody needs to convert their turbo button to actually live up to its name. De-Turbo should be the rated system speed, and pressing TURBO should activate water cooling, powerful (and loud) exhaust fans and overclock the shit out of your CPU.

That's basically what i've done with my FrankenTandy. Except for water cooling and loud fans, of course. In fact i modded the PSU fan to use 5V instead of 12V and it has much less noise now.

A 8MHz -> 16.6Mhz is a pretty good overclock if you ask me.