I get the same noise with a MS-6156 motherboard. I disabled all fans in my setup (the system runs cool enough with passive heatsinks) and run the motherboard out of the case
When a throttle % setting is picked, pretty annoying coil noise comes from the motherboard mosfet area.
Disabling the L1 cache alone doesn't produce any noise.
With lots of fans in an enclosed case it would be a bit harder to hear this.

I'm also getting the audible coil whine when engaging the soft-turbo function of a 430VX mobo FIC VT-501 (by hitting Ctrl-Alt-GreyPlus in DOS). Maybe this is how chipset throttling works - with throttle.exe or otherwise: unused power transforms into vibrations or something.

So I've started experimenting with Throttle. I've got a PIIX4 chipset motherboard, an Asus TX97. Just a plain old TX97, none of those -X or -VX or -LE variants. Throttle runs, allows me to select a level of slowdown, and then... nothing changes. Benchmarks are the same. Doesn't matter if it's the latest Asus BIOS or the 128 GB-modded BIOS. Doing a little digging on ACPI chipsets leads to really cryptic phrases like, "Soft power features require an ATX power supply." This board is currently running on an AT power supply, but I've got an adapter for an ATX power supply with the right three +5VSB/GND/PwrOn cables, and there's even a spot on the motherboard to attach the ATX power button. Is that really what allows the ACPI throttling to work, or am I about to be disappointed? For reference, when Throttle runs even with debug output it's saying it's finding the PIIX4 chipset and setting everything fine. FDAPM will run, say there's nothing in the BIOS for ACPI starting at E000, then suggests using Throttle.

MrSmiley381 wrote:

This board is currently running on an AT power supply, but I've got an adapter for an ATX power supply with the right three +5VSB/GND/PwrOn cables, and there's even a spot on the motherboard to attach the ATX power button. Is that really what allows the ACPI throttling to work, or am I about to be disappointed?

Good morning, me from the past. This is me from the present, which is your future. No, using the ATX power supply doesn't change anything. Sounds like a good excuse to review the source code and the PIIX4 datasheet here, which does say manual stepping is only supported on PIIX4E and PIIX4M revisions of the chipset. Maybe that's the issue? I can still hit speeds between a 286 at 25 and 33 MHz, which is mostly fine, but I was totally hoping to hit some really slow speeds without MoSlo.

MrSmiley381, maybe it's the CPU itself that refuses to get throttled? I've had no luck with a non-MMX Pentium 1 as well on a 430TX with a compatible southbridge. I believe it only works with later CPUs, such as Pentium Pro derivatives (PII, PIII etc.) and, reportedly, AMD K6-#.

Revolter wrote:

MrSmiley381, maybe it's the CPU itself that refuses to get throttled? I've had no luck with a non-MMX Pentium 1 as well on a 430TX with a compatible southbridge. I believe it only works with later CPUs, such as Pentium Pro derivatives (PII, PIII etc.) and, reportedly, AMD K6-#.

Whoops, you'd think I'd mention the CPU when troubleshooting a problem. Bit of an important detail. Yeah, it's a Pentium MMX CPU marked for 233 MHz. I did some checking tonight and Throttle does disable the L1 cache at what appears to be the motherboard enable. Once Throttle disables the cache not even Setmul can reenable it. That tells me Throttle is at least doing some if not all of its job. If the MMX won't respond, I do have a spare K6-3+ around and the BIOS I'm using is already modded to handle it. Might be worth a shot.

DAE know what throttle actually does....over setmule?

kolderman wrote:

DAE know what throttle actually does....over setmule?

Throttle manipulates the power management hardware on your motherboard to disable the CPU cache if desired, then activates throttling control that's also part of the power management hardware. Setmul disables specific CPU features for some CPU's and modifies the multiplier in real time for the others. In most ideal cases you can use both to achieve some very slow speeds. They're two different tools with a similar purpose.