Run a benchmark that updates the score in real-time, like Norton SI or Top Bench. Then try out the various jumpers.

The LED wouldn't come on if the motherboard didn't register that the switch was pressed.

What about any Turbo enable/disable in the Bios?

I'd test it with a jumper, those buttons are not very reliable.

Imperious wrote:

The LED wouldn't come on if the motherboard didn't register that the switch was pressed.

What about any Turbo enable/disable in the Bios?

This.

There are boards where the turbo button doesn't make a significant difference (depending on the actual configuration).

Try disabling the caches in BIOS for slowing down the system.

I noticed that with my AMD 5x86 (which has write back L1 cache), pushing the turbo button had hardly any impact on any benchmark tests.
However, when testing it with a game (like DOOM's timedemo), I could definitely see a difference in speed with the turbo disabled.

However, the above is normally only an issue with CPU's that has L1 write back cache. Your CPU should still have L1 write through cache.

Do your have another CPU to test it with? At least then you will know whether it's a CPU or motherboard problem.

Good call guys/gals. Mobo option had a setting for Turbo Button set to Suspend. I changed it to turbo and it's working as expected 😀

However, it still seems too fast when slowed down.. definitely too fast for booter and older games still. Maybe I need to swap down from DX to SX? Or actually just get off of DX2 and down to DX..

DX and SX are identical at the same clock speed, only difference is that the SX is missing the FPU.

Getting a 486 down to 386 speed is one thing, getting it down to XT speeds is another. You need to fiddle with clock speed and disabling caches, maybe even more.

Oh yeah duh.

Well maybe then just a slowdown program would work for those older XT games, and just the turbo is good enough for those sensitive to speed like wing commander perhaps.

Thanks everyone.

The 1st 2 computer games I ever bought back in 1994 were Wing Commander and X-wing.

I successfully completed Wing commander with the Turbo off on my 486 dx2-66 machine. I actually made it a mission to complete it as I was
upgrading to a Pentium 133 and knew Pentiums didn't have a Turbo switch.