SetMul v1.24 is up:
- Improved accuracy of RDTSC clockspeed measurements.
- Added alternate clockspeed measurement of older processors, like 386/486/Cx5x86.
- More consistent message colors and CPU information display.
- Cleaned up debug output mode, which is triggered with parameter DBG.
- Added option to disable clockspeed measurements with parameter CMD.
- Retain some CPU information functionality within Windows NT based OS.
- Overhauled CPU identification with proper use of extended family and model.

Earlier the Cyrix 5x86 was found to respond to its multiplier jumper/pin while running.
It seems this also goes for later Cyrix Processors such as the MII. This made it possible to switch to 1.0x and 60MHz and work at that speed, even though the system does not want to boot with that setting.
Care has to be taken to close/open the jumper as quick and smooth as possible, otherwise the system will lock up. I think adding a mechanical switch for this job is the best solution.

Thanks gerwin! Keep the updates coming!

Thanks gerwin. You help keep the vintage computing alive and well !

Thanks gerwin for this utility. I have tried using it on my Athlon XP Mobile but the PC freezes when trying to set a multiplier. I've noted SETMUL detects the CPU as a K7 mobile instead of a K8 mobile. Could this be the cause? Note that I haven't tested older versions of SETMUL (not sure where to find them).

The motherboard is a KT7A v1.3 and the CPU an Athlon XP-M 2500+ (AXMH2500FQQ4C) with its voltage reduced to 1.45V.

cde- wrote:

Thanks gerwin for this utility. I have tried using it on my Athlon XP Mobile but the PC freezes when trying to set a multiplier. I've noted SETMUL detects the CPU as a K7 mobile instead of a K8 mobile. Could this be the cause? Note that I haven't tested older versions of SETMUL (not sure where to find them).

The motherboard is a KT7A v1.3 and the CPU an Athlon XP-M 2500+ (AXMH2500FQQ4C) with its voltage reduced to 1.45V.

Athlon XP-M is properly detected as K7. K8 mobile CPUs are completely different, they are all Athlon 64 based. Your problem is that Abit KT7A is not a mobile but a desktop motherboard. So for real time multiplier settings you have to manually tune your chipset. More info:
https://web.archive.org/web/20170822100906/ht … html/Tweaks.htm

Thanks Falcosoft. I will stop my experiments with the multiplier because (although I'm not sure if it's because of the experiments or the modded BIOS) my KT7A 1.3 has become defective. I had a spare KT7A thankfully but from now on I'll only change the multiplier from the BIOS itself.

I benchmarked my k6-3+ to produce a table similar to what clueless1 did here: What's up with all those Setmul switches?

I think it would be really useful as a vogons community resource in the wiki or Google docs to have a reference table for the main processors used with setmul (k6+, via C3, mmx), so people know exactly what to expect. I plan on benching my c3-1000@100 to see how low does it go. I don't currently have a mmx build.

kolderman wrote:

I benchmarked my k6-3+ to produce a table similar to what clueless1 did here: What's up with all those Setmul switches?

I think it would be really useful as a vogons community resource in the wiki or Google docs to have a reference table for the main processors used with setmul (k6+, via C3, mmx), so people know exactly what to expect. I plan on benching my c3-1000@100 to see how low does it go. I don't currently have a mmx build.

I've got something along those lines in a Google Spreadsheet. See the link in my signature about benchmarking systems with cache disabled.

Ah cool that is what I was looking for. I note the best slowdown of mmx/k6/c3 is around "i386DX-16". Yet I thought people were talking about getting down to slow-286 speeds. Anyone know of getting one of those processors down to sub-386 speeds? I note the gimped 486 gets down to 0.4PCP whereas the more modern processors get down to around 1.2 at best. I would love to get either my k6 or c3 down to that level if possible.

Can you stack throttle with setmul? Something I have been thinking about today... given that a Via C3 on a 440bx chipset should be compatible with both, and they use different mechanism to slow the processor.

Sorry I don't understand what you mean by stack throttle. I do use the K6 and C3 as complimentary systems, using specific setmul options that apply to each one.

Interesting, I set my Via Ezra 1000@100 to x3 (300mhz), disable L1/2, disable branch-prediction and I-caches (i.e. everything that setmul supports for the C3)...and it came close but not as slow as the K6.

3dbench lowest=16.9
Speedsys lowest=16.7

So for me at least, my k6-3+ is my King of Slow. I will try a MMX when I get time one day.

Throttle is slow down utility, like setmul that, that uses clock skipping. Throttle slows down the CPU in a different way than setmul does, so it might be possible to use them together to get even slower.

The Ezra can get down to sub 8 speedsys, but only at a X3 muliplier and 50fsb. Try the lowest settings your processor and motherboard will put up with.

EDIT: Typos

I just wanted to confirm, in case no one has in the past, that this utility can successfully turn the L1 cache on or off on UMC U5S-SUPER 486 CPUs (which effectively clocks them down to 386DX level performance). Very useful for building a system that can play both Ultima VII (L1E) and Wing Commander (L1D). De-Turbo takes it down to even lower speeds (Fast-286/Slow-386SX).

Can anyone confirm whether Setmul can disable the cache on Slot-A or Socket-A processors?

Regarding Socket A:
L1 cache can be disabled for the command prompt one way or another. I don't remember exactly, but if it does not work I will make it work 😀 . It is rather simple. But I don't think there is something for L2 cache yet.
Besides that, RoberMC suggests in this topic that KT133/A based boards do not support software multiplier switching. Which includes those socket A boards with an ISA slot.

I'll be building a KX133 Slot-A Athlon or a KT133 Socket-A Duron system soon, I will test it out and let you know if you are willing to try developing in that direction. 😎 I am hoping disabling L1 cache on either CPU would bring it down to a nice 386/486 speed..

Anyone tried SetMul with a Duron on a SocketA system? I have an Abit KT7A and I'm thinking about downgrading my AthlonXP 1500+ to a Duron 700 in the hopes of getting more slowdown choices.

Currently, SetMul only allows me to disable the L1 cache on the AthlonXP which puts it at around 386 levels, and that's really awesome. However, I'd like something not quite as slow for mid-late 90s games like WarCraft 2 and Red Alert which have issues with overly fast screen scrolling.

Is it possible for SetMul to change the multiplier on the Duron and make it run at something like 200 MHz? For reference, the multiplier settings in my BIOS only go down to 5x.

Aren't all Socket A processors multiplier locked?

appiah4 wrote on 2020-02-18, 08:05:

Aren't all Socket A processors multiplier locked?

I can freely change the multiplier on the Athlon XP that I'm currently using. However, that one is detected as "Unknown CPU" since it's too new for the motherboard, so that may be why. Back when I first bought this computer I had an older Athlon Thunderbird, but I don't remember whether or not I was able to do anything with its multiplier.

The KT7A has a "User Define" setting in its BIOS which lets me change a bunch of stuff, including the multiplier. Here's a screenshot from the manual: