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Wht's the fastest unlocked PII?

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First post, by AlessandroB

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I have a PII 266 that can accept lower mutiplier but not highter than 266 i think. what's the best to buy (models and revision)? tnks

Reply 2 of 32, by RacoonRider

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AlessandroB wrote on 2020-02-07, 00:36:

I have a PII 266 that can accept lower mutiplier but not highter than 266 i think. what's the best to buy (models and revision)? tnks

Why would you want higher multiplier? In most cases the key to overclocking is lower multiplier and higher FSB.

Note that Klamath core Pentium II is an early design that suffers from issues typical to bleeding-edge computer componnets - it's hot and running close to its maximum speed from the box. In other words, not really overclockable.

And as far as I know, most if not all later PIIs have locked multipliers. Unless you manage to get your hands on an engineering sample.

Reply 3 of 32, by dionb

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A lot of P2-333 Deschutes were unlocked. That made them great for overclocking as you could lower the multiplier and run them at 100MHz FSB. Most clocked well past 400MHz.

Reply 5 of 32, by foil_fresh

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how low can an unlocked P2 go? 66 x 2 ?

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 6 of 32, by AlessandroB

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derSammler wrote on 2020-02-07, 11:33:

Why not just get the 450 MHz PII if you want the fastest one? No need to overclock that one either.

because i not have 100mhz bus.

P2 con go at 66x2=133Mhz in its lowest speed

Reply 7 of 32, by AlessandroB

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Today i did this test:

I set up the computer according to the table below as if it were a Pentium2 333Mhz (actually it is a P2 266)

and the result was what you see in the screnshoot below ...

Why???

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Reply 8 of 32, by The Serpent Rider

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That's infamous bug/feature of multiplier unlocked Pentium II.

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Reply 10 of 32, by foil_fresh

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AlessandroB wrote on 2020-02-07, 12:49:
derSammler wrote on 2020-02-07, 11:33:

Why not just get the 450 MHz PII if you want the fastest one? No need to overclock that one either.

because i not have 100mhz bus.

P2 con go at 66x2=133Mhz in its lowest speed

any particular version? or can they all underclock

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 11 of 32, by The Serpent Rider

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Last time I checked, certain multiplier can somehow force some sort of "throttling". All utilities report 5x multiplier with 20-26 Mhz bus and the system overall feels very slow.

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Reply 13 of 32, by Doornkaat

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I believe the highest multiplier to work on a Pentium II is 5x. That makes the 333MHz the fastest 66MHz FSB PII. They're not too uncommon imho so it might be easiest to just buy one instead of looking for a special SSpec from a certain date and location that promises good cache chips and an unlocked core that often overclocks well.

I know this isn't exactly what you asked for but if you're limited by the FSB fiddling with multipliers doesn't seem like a practical approach. Sorry if I'm not being helpful here.

AlessandroB wrote on 2020-02-07, 12:49:
derSammler wrote on 2020-02-07, 11:33:

Why not just get the 450 MHz PII if you want the fastest one? No need to overclock that one either.

because i not have 100mhz bus.

P2 con go at 66x2=133Mhz in its lowest speed

If you simply want the fastest CPU for your motherboard that's probably going to be the 533 MHz Mendocino Celeron on a Slotket.

Reply 14 of 32, by gerwin

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The Serpent Rider wrote on 2020-02-07, 17:04:

Last time I checked, certain multiplier can somehow force some sort of "throttling". All utilities report 5x multiplier with 20-26 Mhz bus and the system overall feels very slow.

I disagree.
Speedsys readout is just messing up. My SetMul tool does not say such.
Pentium 2 Klamath core has a 2.0x multiplier setting with working L2 cache. Also one 2.0x setting which disables L2 cache.
Pentium 2 Deschutes core has only a 2.0x multiplier setting which disables L2 cache.
Pentium 2 Deschutes cores produced after a certain date are multiplier locked.

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Reply 15 of 32, by pixel_workbench

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The replies in that cpuworld thread are wrong. The highest clocked P2 with an unlocked multi is a 400mhz version, with stepping dA1. That's about week 38 of 1998 or older.

The advantage of the 350mhz and 400mhz models is that the L2 cache chips are cooled by the heatsink. Older models do not cool the cache chips.

There are two disadvantages though. 1 - the 333mhz version has a higher default multiplier, and because these multipliers are only unlocked downward, it offers more flexibility than the faster models. 2- the faster models use cache chips with looser timings, so clock for clock the P2 333 is slightly faster than the 400mhz variant. A P2 333 running at 4x100 is about as fast as a P2 400 running at 415 or 420.

I have both a 333 and 400 version with unlocked multipliers, and although my P2 333 can run stable at 400mhz, I use the P2 400 in my slot 1 build simply bacause I don't want to fry the uncooled cache chips by overclocking the P2 333.

My Youtube Channel
P2 400 unlocked / Asus P3B-F / Voodoo3 3k / MX300 + YMF718

Reply 16 of 32, by j^aws

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Fastest I've used is an unlocked PII 400 Mhz. It easily clocks to 450 MHz (IIRC, 4.5 multi x 100 FSB). I tried overclocking t0 500 and 533 MHz, but no POST. Probably due to the cache chips being out of specification.

If you can get an unlocked Coppermine or Tualeron/ Tualatin, they are more flexible; the lower end of a PII is better handled with a VIA C3 on Slot 1/ Socket 370.

Reply 17 of 32, by H3nrik V!

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j^aws wrote on 2020-02-10, 00:00:

If you can get an unlocked Coppermine or Tualeron/ Tualatin, they are more flexible; the lower end of a PII is better handled with a VIA C3 on Slot 1/ Socket 370.

Does unlocked P!!! even exist? At least only as engineering samples, I would believe

Reply 18 of 32, by gerwin

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H3nrik V! wrote on 2020-02-10, 05:52:

Does unlocked P!!! even exist? At least only as engineering samples, I would believe

Yes, Engineering/Qualification Samples only. And not all of those have a free multiplier.

IMO an unlocked Pentium II system still has its charm, regardless of the other options mentioned. Compared to Pentium 1/mmx it has LFB Write Combining, which makes it much better at handling SVGA games.

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Reply 19 of 32, by pentiumspeed

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Very interesting case where PII is useful with SVGA games, still have too fast issues that one needs to slow the PII down and still use LFB W-C?

Secondly, Which video card to use with the LFB W-C?

Cheers,

Great Northern aka Canada.