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Which Pentium IIs can be underclocked?

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Reply 40 of 202, by Tetrium

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I could try memtest86, it reports the L2 cache.
I'm correct that it's possible to disable the L2 cache on P2's in the BIOS, right?
If I set up a test rig, disable the L2 at normal speed and then run memtest86 I could check if memtest86 correctly identifies the L2 cache or not

Reply 41 of 202, by TheLazy1

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You can try cachechk but I found it to be a bit flakey.
On a 486 board I have that definitely has cache installed it would be reported missing unless I manually set main ram timings to the fastest setting.

It would always show access <= cache size being faster than main ram but I guess not at large enough of a margin for it to believe it was anything but a fluke?

[Edit]
Or maybe a quake timedemo with and without L2 enabled in the bios?

Reply 42 of 202, by swaaye

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speedsys or cachechk in DOS.

In Windows you have lots of choices. CPU-Z, Everest Home Edition and Sisoft Sandra will definitely be able to tell you if a Pentium II has its cache enabled or disabled.

The system should feel quite sluggish without the L2 cache. Disabling the L2 turns your PII into a nasty Covington Celeron basically.

Reply 44 of 202, by Tetrium

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I'm sure I have a couple boards that'll go to 50Mhz fsb but the ones I can remember are LX, not BX. When I have time, I'll check which ones go under 66Mhz and report back 😉

Edit:Chances are you'll have better luck finding an underclockable LX board then an underclockable BX board

Reply 46 of 202, by Tetrium

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TheLazy1 wrote:

Does anyone know about lowering the vcore on a 440ZX board?
There are no options in my bios for it unfortunately.

That really depends on who manufactured your motherboard. Usually OEM's have less options in their BIOS then retail motherboards do.
It's not really a chipset thing, those usually have many options that are left out by companies like Compaq etc.

Reply 48 of 202, by Tetrium

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I think lowering the VCore on this board isn't gonna happen. This is more a budget board and those often come (or came!) with less flexibility.
I don't know a slot 1 board from the top of my head that can undervolt CPU's. Perhaps there is one that has undocumented jumper settings for this.

How's the underclocking on this board btw?

Reply 49 of 202, by TheLazy1

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Best I can do is my P II 350 at 233MHz, I might be able to find another chip to try but chances are it'll have the same stepping.
It does have a 2x multi though I believe so with an unlocked chip 133MHz should be possible.

Maybe even lower if the fsb can be lowered in software, but since it's jumpered I kinda doubt it.
Even still, most of the software fsb stuff is all windows.

[Edit]
I'm trying for the lowest possible power consumption here, so it's a shame that the vcore is going to be locked.
Unless I find a hardware mod...

Reply 50 of 202, by Tetrium

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I think you'll have better luck reducing power consumption by underclocking then by undervolting. Try to find a semi-unlocked -->Deschutes<-- P2 and underclock the hell outa it!!1 ;D

Also, if you can find an LX board, you'll have a better chance it will support the lower FSB's. Together you could go as low as 100Mhz 😉

Reply 51 of 202, by gerwin

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Another interesting low power solution: Buy a 533Mhz/133FSB coppermine Pentium III CPU and set it at 266MHz/66FSB.

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

Reply 52 of 202, by Tetrium

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Idd, those Coppermines have about half the power consumption of the Deschutes. However, I know of no LX board that will support it and it'll be harder finding a BX board that can go below the magic 66 😜

Reply 53 of 202, by ux-3

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In a way, an LX isn't going to be a neat solution. It likely won't run well with power hungry AGP cards, like Voodoo3 3000 or Voodoo5 5500. Once you sacrifice all those upper end options, you are confining yourself to a very limited speed range. You might be better of with a super socket 7 board, where you can use anything from p1 mmx at 133 MHz up to an K6-2/3 at about 500 MHz.

Is it possible to use a mobile Pentium cpu with unlocked multi on a slot1 adapter?

I currently favor the p2-333 & P3 swap solution on a BX board.
To manipulate speed, one can use fsb, multi on the p2, L1, L2 Cache off.

I found that a P3 from 550 to 800 with disabled L1 cache just offers the right speed for wing commander 1.

I am now trying to put together such a machine without the compromises, that my current crate still has. I will try an Asus p3b-f rev 1.04 with two isa slots and a Voodoo5 and a Voodoo1 or Voodoo2 as a junior partner. The speed should be in the range of 133 to 1000 Mhz. The alternative is using a mobile athlon, which can use Multi 3 and up, as well as fsb 100 and up. That would give 300 to 2200 MHz.
With L1 off, you get the performance from slow 286 to 486 by using the multi.
Edit: Drawback on the Athlon is the lack of Isa slots. I have not figured out yet, how I can use my Barton XP-M on a KT133 board, which offers 1xISA.

Reply 54 of 202, by Tetrium

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ux-3 wrote:
In a way, an LX isn't going to be a neat solution. It likely won't run well with power hungry AGP cards, like Voodoo3 3000 or Vo […]
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In a way, an LX isn't going to be a neat solution. It likely won't run well with power hungry AGP cards, like Voodoo3 3000 or Voodoo5 5500. Once you sacrifice all those upper end options, you are confining yourself to a very limited speed range. You might be better of with a super socket 7 board, where you can use anything from p1 mmx at 133 MHz up to an K6-2/3 at about 500 MHz.

Is it possible to use a mobile Pentium cpu with unlocked multi on a slot1 adapter?

I currently favor the p2-333 & P3 swap solution on a BX board.
To manipulate speed, one can use fsb, multi on the p2, L1, L2 Cache off.

I found that a P3 from 550 to 800 with disabled L1 cache just offers the right speed for wing commander 1.

I am now trying to put together such a machine without the compromises, that my current crate still has. I will try an Asus p3b-f rev 1.04 with two isa slots and a Voodoo5 and a Voodoo1 or Voodoo2 as a junior partner. The speed should be in the range of 133 to 1000 Mhz. The alternative is using a mobile athlon, which can use Multi 3 and up, as well as fsb 100 and up. That would give 300 to 2200 MHz.
With L1 off, you get the performance from slow 286 to 486 by using the multi.
Edit: Drawback on the Athlon is the lack of Isa slots. I have not figured out yet, how I can use my Barton XP-M on a KT133 board, which offers 1xISA.

Pentium 1's are incompatible with P2 motherboards, it won't work.
The LX indeed have problems with their AGP ports but that can be solved by using a PCI Voodoo 3, those are quite common.
In a system build for low power consumption a Voodoo 3 wouldn't be the best choice anyway

There do exist a number of KT133A boards with ISA slots, iirc it was the last (non-industrial) chipset that had support for ISA.
There do exist Coppermine ES, but good luck finding one

Reply 55 of 202, by retro games 100

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ux-3 wrote:

I have not figured out yet, how I can use my Barton XP-M on a KT133 board, which offers 1xISA.

Interesting. Are we talking QDI Kinetiz 7E-A mobo here? If yes, there's 3 things to consider. 1) What's the mobo's PCB revision number? You can see this in the bottom right hand corner, I think. (It's in one of the corners.) Your best bet is the PCB that has "2.0(2.3)" written in the corner, and also, the caps are the silver coloured ones, not the brown coloured ones. 2) What is your BIOS ROM version? You're best bet is the very last 4.1 version. 3) What XP-M CPU are you using? I know for sure that the 2400+ rated CPU (1800mhz real clock speed) works fine in this particular board. I vaguely recall that other XP-Ms did not work, for example the 2200+ rated CPU.

However, when you said "KT133 board", you may not be referring to the QDI Kinetiz KT133A board at all...

Reply 56 of 202, by TheLazy1

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I was thinking about that also, the power consumption would be similar but with a lot more available performance.
What about a VIA processor with a 370->Slot 1 adapter?

[Edit]
Maybe I should do some power consumption measurements and split off into my own thread instead of hijacking this one 😀

Reply 57 of 202, by Tetrium

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TheLazy1 wrote:

I was thinking about that also, the power consumption would be similar but with a lot more available performance.

Nope, Coppermines actually consume less then half of what a Deschutes (and Katmai) consume.
Theres a great page about CPU power consumption here:
http://mysite.verizon.net/pchardwarelinks/elec_pentium.htm

And about the VIA's, they do indeed consume much less power but not all slot 1 boards will support it. Even if you flash the BIOS many boards can't cope with the very low voltage these chips want. If you decide to go the VIA route, get one of the early ones as those aren't multiplier locked 😉

Btw, I bought 2 Watt meters once. With them I can measure how much Watts a computer system consumes. Veeery nice 😉

Reply 58 of 202, by ux-3

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Tetrium wrote:

Pentium 1's are incompatible with P2 motherboards, it won't work.

Who would have thought? 😉

The LX indeed have problems with their AGP ports but that can be solved by using a PCI Voodoo 3, those are quite common.

You realize that the PCI versions draw a lot more power, which you can easily spot been wasted on their voltage regulators. Just don't burn your fingers.

Reply 59 of 202, by Tetrium

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ux-3 wrote:
Who would have thought? :wink: […]
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Tetrium wrote:

Pentium 1's are incompatible with P2 motherboards, it won't work.

Who would have thought? 😉

The LX indeed have problems with their AGP ports but that can be solved by using a PCI Voodoo 3, those are quite common.

You realize that the PCI versions draw a lot more power, which you can easily spot been wasted on their voltage regulators. Just don't burn your fingers.

Are you sure it uses more power then the AGP version? Why is that?
Btw, he wants as little power consumption as possible so a Voodoo 3 of any version is out of the question.
If he wants low power consumption, I'd actually sugest using an S3 of some sorts, or if he wants AGP then a Sis 6236 or a TNT2 M64. Those have very low power consumption and don't waste a PCI slot (yes I know the sis 6236 has very crappy performance 😜 )