VOGONS


Pentium 2 @ 133 mhz project ,done

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First post, by dragonkn

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Motherboard:
Gigabyte ga686lx4 ; intel 440LX chipset
CPU:
Unlocked Klamath 300 mhz

I got manual for this motherboard and there is x3 to x5.5 ratio
Can you help me get 'sick' x2 ratio for 133 mhz?

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Last edited by dragonkn on 2020-03-04, 15:35. Edited 3 times in total.

Reply 4 of 20, by gerwin

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Klamath core CPU multiplier 2.0x with functional L2 cache should be like this:

1-2-3-4
ON-off-off-ON
or
ON-off-off-off

dragonkn wrote on 2020-03-02, 21:28:

Before i will start messing around 😀
Do you guys think i can broke something if i try to set some random ratio on this motherboard?

Sometimes you get a non-booting combination and in some cases an unintended overclock (though Klamath core maxes out at 5.0x AFAIK). Which is solved by changing the setting and rebooting again. I never managed to break anything with the multiplier dipswitches on slot 1 boards.

--> ISA Soundcard Overview // Doom MBF 2.04 // SetMul

Reply 5 of 20, by dragonkn

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gerwin wrote on 2020-03-02, 23:05:
Klamath core CPU multiplier 2.0x with functional L2 cache should be like this: […]
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Klamath core CPU multiplier 2.0x with functional L2 cache should be like this:

1-2-3-4
ON-off-off-ON
or
ON-off-off-off

Many thanks!I will be home in two days and will post results!

Reply 6 of 20, by Baoran

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gerwin wrote on 2020-03-02, 23:05:
Klamath core CPU multiplier 2.0x with functional L2 cache should be like this: […]
Show full quote

Klamath core CPU multiplier 2.0x with functional L2 cache should be like this:

1-2-3-4
ON-off-off-ON
or
ON-off-off-off

dragonkn wrote on 2020-03-02, 21:28:

Before i will start messing around 😀
Do you guys think i can broke something if i try to set some random ratio on this motherboard?

Sometimes you get a non-booting combination and in some cases an unintended overclock (though Klamath core maxes out at 5.0x AFAIK). Which is solved by changing the setting and rebooting again. I never managed to break anything with the multiplier dipswitches on slot 1 boards.

Are you about that?
on-off-off-on is suppose to be 5x multiplier and on-off-off-off is suppose to be 5.5x multiplier. Those are already shown in the picture.
I have a different brand and model P2 motherboard that does match all those 3x-5.5x settings that are in the picture of the first post of this thread and based on that the 2x multiplier should be

off-off-off-off

Reply 7 of 20, by foil_fresh

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hey i have a lucky star 440bx motherboard which shows a possible 2x multiplier in BIOS. i dont have a p2 to test it but want to try out a klamath to get some sub 200mhz speeds while using SB-link for a ymf724 soundcard in DOS. also keeping the ability to pump up the multi for normal windows 98 use.

does anyone reckon the 2x in bios will actually mean 2x?

my solution currently is a k6-2+ 550 (at either 200mhz or 550mhz) using setmul but the mainboard doesn't have sb-link. using a p2 klamath means i can get run from 133mhz to 333mhz right? a p2 at 333 probably runs as well as the k6-2+ 550 so i'm not missing out on high end performance, but i'm gaining more options for lower speed.

cheers

Pentium MMX 166MHz / Shuttle HOT591-p / S3 Trio3d2x / SB 16
Pentium II 266MHz / Lucky-Star 6ABX2V / Riva128 / AWE64 / AW744L
Pentium III 950 MHz / SY-7VBA / Voodoo 3000 / Aureal Vortex 2
Pentium IV 3.4GHz/ GA-8S655FX / Geforce 6800 GT / Audigy

Reply 8 of 20, by dragonkn

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Baoran wrote on 2020-03-03, 04:44:
Are you about that? on-off-off-on is suppose to be 5x multiplier and on-off-off-off is suppose to be 5.5x multiplier. Those are […]
Show full quote

Are you about that?
on-off-off-on is suppose to be 5x multiplier and on-off-off-off is suppose to be 5.5x multiplier. Those are already shown in the picture.
I have a different brand and model P2 motherboard that does match all those 3x-5.5x settings that are in the picture of the first post of this thread and based on that the 2x multiplier should be

off-off-off-off

on-off-off-on is same as 5x , that is true but on-off-off-off is different than 5.5 multipler. Take a look on the photo first switch is number 4, Gerwin wrote first one with 1.
Sure i will try off-off-off-off when will be at home.

foil_fresh wrote on 2020-03-03, 07:53:

using a p2 klamath means i can get run from 133mhz to 333mhz right?
cheers

AFAIK all pentium 2 before 33 week of 1998 can be at lest downclocked if motheboard supports it. After that you need to do stability test (cpu benchmark, memtest etc)

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Reply 9 of 20, by Baoran

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dragonkn wrote on 2020-03-03, 10:52:
Baoran wrote on 2020-03-03, 04:44:
Are you about that? on-off-off-on is suppose to be 5x multiplier and on-off-off-off is suppose to be 5.5x multiplier. Those are […]
Show full quote

Are you about that?
on-off-off-on is suppose to be 5x multiplier and on-off-off-off is suppose to be 5.5x multiplier. Those are already shown in the picture.
I have a different brand and model P2 motherboard that does match all those 3x-5.5x settings that are in the picture of the first post of this thread and based on that the 2x multiplier should be

off-off-off-off

on-off-off-on is same as 5x , that is true but on-off-off-off is different than 5.5 multipler. Take a look on the photo first switch is number 4, Gerwin wrote first one with 1.
Sure i will try off-off-off-off when will be at home.

You are right if he meant the numerical order instead of order in the picture. On my motherboard manual on-off-off-off is 2.5x and off-off-off-off is 2x so it probably doesn't hurt the cpu to try both.

Reply 10 of 20, by PARKE

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Assuming that most if not all PLL-based frequency multipliers in that generation of motherboards are based on the same principle the below settings of this extended version of your multiplier could work:

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The Klamath that I once tested did however not support L2 cache at multiplier 2x:

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Reply 11 of 20, by lordmogul

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About your cache issue on 2.0x multiplier:
I read The Ultimate 686 Benchmark Comparison today and stumbled upon this:

feipoa wrote on 2013-02-14, 10:58:

(...)
In most cases, if you try to run a PII Klamath with a 2.0x multiplier, the onboard L2 cache will get disabled on motherboards with a chipset other than a 440FX. For the VIA Apollo Pro chipset (and 440BX), it was discovered that setting the CLKMUL jumper to 5.0x allows the CPU to run at 2.0x with L2 enabled. While some speed measuring programs may indicate the FSB as 26.7 MHz, multiple tests seem to indicate that the FSB is actually at 66 MHz.
(...)

P3 933EB @1035 (7x148) | CUSL2-C | GF3Ti200 | 256M PC133cl3 @148cl3 | 98SE & XP Pro SP3
X5460 @4.1 (9x456) | P35-DS3R | GTX660Ti | 8G DDR2-800cl5 @912cl6 | XP Pro SP3 & 7 SP1
3570K @4.4 GHz | Z77-D3H | GTX1060 | 16G DDR3-1600cl9 @2133cl12 | 7 SP1

Reply 12 of 20, by _UV_

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From my experience with ABIT and ASUS BX boards early BIOS allowed 2x multiplier and cache was disabled with a possible 20-30% not to boot up or instabilities even in DOS. It was later patched with 3.0x as lowest possible with full stability.

Reply 13 of 20, by dragonkn

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It's working! I did use x5 multiplier and it realy is x133 with L2 enabled.
Today I will post benchmark with different clocks.

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Reply 14 of 20, by dragonkn

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I did tests and benchmarks @133 mhz to @300 mhz (i tried oc to 366 but it's not working).
Extended version of CLKMUL setup from PARKE is working great.
I didn't saw any problems and instability, if any problem will occur i will post in this thread.
Thanks for help! 😀

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Reply 16 of 20, by gerwin

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@ PARKE / lordmogul / UV:
In case L2 cache gets disabled with such a 2.0x Klamath core setup, then the wrong multiplier request signal is being send. There are only two proper request signals with working L2 cache , which I posted earlier. On a jumperfree motherboard the proper options may not be available, or they are hidden behind the wrong description. 2.0x was not intended for customer use.

Also @PARKE. Multiplier selection has little to do with the motherboard, it depends on the CPU. All the motherboard can do is send a 4 bit request signal to the CPU at bootup.

--> ISA Soundcard Overview // Doom MBF 2.04 // SetMul

Reply 18 of 20, by PARKE

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gerwin wrote on 2020-03-04, 16:48:

@ PARKE / lordmogul / UV:
In case L2 cache gets disabled with such a 2.0x Klamath core setup, then the wrong multiplier request signal is being send. There are only two proper request signals with working L2 cache , which I posted earlier. On a jumperfree motherboard the proper options may not be available, or they are hidden behind the wrong description. 2.0x was not intended for customer use.

Also @PARKE. Multiplier selection has little to do with the motherboard, it depends on the CPU. All the motherboard can do is send a 4 bit request signal to the CPU at bootup.

Understood, sort of....
When you write: [2.0x was not intended for customer use.] you mean by Intel ?
Do you happen to have spec sheets for this kind of multiplier that you can share ?

Reply 19 of 20, by gerwin

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PARKE wrote on 2020-03-04, 17:18:

Understood, sort of....
When you write: [2.0x was not intended for customer use.] you mean by Intel ?
Do you happen to have spec sheets for this kind of multiplier that you can share ?

In this older topic I explained the same thing:
50 to 133MHz FSB on a BX Mainboard
There I noted that an unlocked Slot 1 CPU probes these CPU pins at bootup:
"LINT[1], LINT[0], A20M#, IGNNE#."
These pins are used te read the 4 bit multiplier request signal from the motherboard. 4 bit means a maximum of 16 values, a maximum of 16 different multiplier options.
Which multipliers result from which request signal is to some degree an experimental thing. Because the obscure ones like 2.0x and the ones on engineering samples are usually not mentioned in Intel datasheets. They are leftovers from intel development usage.
The multiplier selection matrix for Klamath is a bit different from the Deschutes, which is again a bit different from Coppermine-early (ES). Coppermine-late/Tualatin (ES) has a way different selection of 16 multiplier choices.

--> ISA Soundcard Overview // Doom MBF 2.04 // SetMul