Most Miserable Frequency Reached with a Duron

[ludek]

Hi, so here is my attempt to attack the CPU-Z Validator World Record, this one -> "[LULZ] Most Miserable Frequency Reached with a Duron". https://valid.x86.fr/records.html

So here it was when I started a week ago:

My first approach was to collect some data:
1. cheapie 307 MHz (8 * 38.38 MHz); Duron 800(?), VIA KT133, SDRAM
2. TerraRaptor 333.26 MHz (5 * 66.65 MHz); Duron L1 mod probably, NF2
3. 0xCats 334.06 MHz (5 * 66.81 MHz); KT266
4. trodas 398.49 MHz (6 * 66.41 MHz); KT266
5. "GIGABYTE" 501.19 MHz (5 * 100.24 MHz); KT133 Gigabyte 7ZXR
6. tukz 531 MHz (8 * 66.38 MHz); SiS 735, K7S5A

The slowest Duron I found on Cpu-world database is 600MHz, so 6x100. So Terraraptor and OxCats done L1 mod (unlock multiplier). I did this too. The problem is you can set multiplier only by BIOS. (or maybe there is a software to modify non-mobile CPUs? CrystalCPUID doesnt work).

Since I have a LOTS of motherboards I tried the slowest:
ECS K7S5A (SIS, PLL:BIG-STEPS, 66.66 MHz is lowest) 100/75/66 
ECS K7S6A (SIS, PLL:BIG-STEPS, 66.66 MHz is lowest)(the same IC)
ECS K7VZA (VIA KT133A, PLL:BIG-STEPS, 100 MHz is lowest)
ABIT KG7-LITE (AMD RARE Chipset, did 76MHz x7 (536MHz CPU))
GIGABYTE GA-7VA (VIA KT400, good one <59 MHz, but no multi settings in BIOS, ended up with dead MB, because my MODBIN skills are weak) did 60MHz x7 (421MHz CPU)  
ASUS A7V600-X (VIA KT600, below 100MHz unstable)
ASUS A7N8X-E (FTW!)  Nforce 2

 

So here is some photo:

I was able to set 5x mul in BIOS and using pecular technique I was able to reach the "Bradycardia", The Duron 700 downclocked to 165 MHz (33,0 MHz x 5). The problem now is software: ClockGen goes down to 66MHz, CPUFSB also. One program I found was: "6.08-nvidia-system-tools" (71,8 MB) and minimum is 50 MHz. But it supports OC Profiles saving and loading. So I editted a profile using Notepad. For example changed 50MHz to 40 MHz. Done.

So here is my technique: [video] (nothing special after first windows crashed, i have even make mistake while saving profile (3MHz instead 33)
https://drive.google.com/file/d/13CyqlC27FhQNm2WcqBV0YVDkr7SMQsEp/view?usp=sharing

Future:
I also want to try the newer Durons like Applebread L1 mod. Newer CPUs were allowing to set 3x mul AFAIR. Am I correct?
I also want to try this trick on other NF2 boards.
Maybe there is a software to modify non-mobile CPUs? CrystalCPUID doesnt work.

[Tzk]

Few thoughts:

1. you can't change multi on-the-fly on NF2

2. lowest multi is either 4 or 5, 3x is not possible. You can read the AMD datasheets for the available multis. iirc lowest is 5x...

3. there's Infrareds NF2 Xtreme tweaker available for NF2, however the lowest it can do is 50MHz. Maybe @I.nfraR.ed can lower that limit, so you can test if you can reach as low as 33Mhz?

And at last: nice job, well done!

[I.nfraR.ed]

I have removed the lower limit. The steps will be stupidly small (0.05MHz), but hopefully it works.

I'm not sure what is the lowest supported frequency by the integrated PLL in nForce2, but you can try.

Lowest multi should be 3x, but not sure on which generation.

https://github.com/torvalds/linux/blob/4cee37b3a4e68c42b867c87a6218e11bc571ba66/drivers/cpufreq/powernow-k7.c#L78

NForce2Xtreme-v1.1-beta19-mod.zip

Edited December 11, 2022 by I.nfraR.ed

[ludek]

Oh thanks! I will try. How this platform clocks PCI/AGP/MEM? Is it like Pentium 3 (33:66:100:100)? or stable 33/66 and variable FSB:MEM?

I saw that the only stable divider was mem 100 FSB 100 and going down. If I set in BIOS settings for example mem 200 and fsb 100, no boot or no downclocking. Is the 1:1 the only stable option to be able to manipulate fsb frequency from the OS?

[I.nfraR.ed]

1:1 is always preferred, but there are other dividers that work, just not on every FSB, you have to find a working combination.

There's a PCI lock, so no matter the FSB you have AGP and PCI locked and you can control the PCI bus frequency independently from the FSB.

Some of the dividers boot (e.g. lower memory compared to FSB), but they work up to 220 and then you need to clock in Windows.

This is how the records are achieved, although I think it would be possible to use TCCD for 1:1.

https://hwbot.org/hardware/chipset/nforce2_ultra_400/

There's also an "auto validation bot" in the tweaker, which you can let validate the FSB for you at least for the preliminary testing, then maybe try manually for the last extra MHz, however in my testing the auto bot was able to beat me and validate higher . It can only validate higher FSB, but I can add the opposite direction too (downclocking). You would probably need to tweak the registers though and you definitely need mod bios.

My tweaker is not necessarily the best tool for the job, it has a better granularity than Clockgen, but there might be things I don't know, since most of the PLL work done for the tweaker is reverse engineering and "trial and error" method, due to lack of documentation. Luckily there is a linux driver for the PLL I was able to port and extend for my needs.

PS: This, for example, has the memory higher than the FSB: https://hwbot.org/submission/2557243

You probably need a 2T bios for TCCD to work at this frequency on NF2 (don't quote me on that though).

This is the current record on s.A, I still haven't found the time to try and replicate it: https://hwbot.org/submission/2640212_stelaras_memory_frequency_ddr_sd_ram_305.7_mhz

Everybody thought 300.7 was the hard limit, but Greek guys found a way to lift that limit.

This platform is my all-time favorite, maybe it helps that my first PC I bought with my own money was socket A based 

Edited December 14, 2022 by I.nfraR.ed