While I was resurrecting one of my P2 based project, I remembered about the Unlocked PII CPUs, and was searching for the list. For convenience sake, here is the list.
The results are from our own members here and all credits to them. I just wanted to put up this list for easy reference. Any more updates are welcome.
Thanks to everyone who helped to check these CPUs.
Original thread here.
Since it may come useful to someone else:
SL2U7 (450 Deschutes) is locked
SL2S7 (400 Deschutes) MALAY is unlocked
Nemo1985 wrote on 2022-02-16, 08:24:Since it may come useful to someone else:
SL2U7 (450 Deschutes) is lockedSL2S7 (400 Deschutes) MALAY is unlocked
I think the date of manufacturing on those might be important, more than the sSpecs ...
Please use the "quote" option if asking questions to what I write - it will really up the chances of me noticing 😀
H3nrik V! wrote on 2022-02-16, 08:57:Nemo1985 wrote on 2022-02-16, 08:24:Since it may come useful to someone else:
SL2U7 (450 Deschutes) is lockedSL2S7 (400 Deschutes) MALAY is unlocked
I think the date of manufacturing on those might be important, more than the sSpecs ...
Well intel locked the multiplier around the week 31 (1998), but not every sspec is unlocked before that date.
My unlocked p2 400 is week 14
Only my eralier produced Deschutes PII CPUs:
Pentium II 333 SL2QF dA0 produced in week 29/1998 Malay unlocked from 2x until 5x (5.5x gaves me a black screen)
Pentium II 400 Sl2S7 dA1 produced in week 23/1998 Malay, NOT unlocked, always runs with 400 MHz (100FSB) with 2x until 5x multiplier setting
Interesting, because this Sl2S7 stepping was produced before week 30 and should be unlocked. Would be interesting why...I have looked for this PII 400 version and <week 30/1998 Malay production, because I wanted a unlocked PII 400 Deschutes...
Here are the specs of this locked Sl2S7 PII 400 CPU for insider who might know more :
80523PY400512EC SL2S7
98231351-1591 MALAY
NostalgicAslinger wrote on 2023-06-27, 17:16:Here are the specs of this locked Sl2S7 PII 400 CPU for insider who might know more :
80523PY400512EC SL2S7
98231351-1591 MALAY
Strange Indeed. I have a later one from week 30 which proved to be unlocked. As was noted here:
Re: Downclocking intel cpu help?
SL2S7 400 (dA1) Tetrium has '98-30 Malay - unlocked Malik has '98-25 Philippines - unlocked Skyscraper has '98-31 Malay - unlock […]
SL2S7 400 (dA1)
Tetrium has '98-30 Malay - unlocked
Malik has '98-25 Philippines - unlocked
Skyscraper has '98-31 Malay - unlocked
Gerwin has '98-30 Malay - unlocked
Gerwin has '98-33 Philippines - locked
Edit: recently wbc also made this tool, which makes these Pentium II deschutes cores more useful at their 2.0x clock setting:
P6Cache v0.01a - Pentium II/III/Celeron L2 Cache Management utility
Which Pentium IIs can be underclocked?
--> ISA Soundcard Overview // Doom MBF 2.04 // SetMul
I have tested this CPU on two different mainboards, the Slot 1 Oc King Abit BE6-II i440BX with the nice CPU Soft Menu III, which also allows L2 Cache Latency settings and the FIC VL-601 i440LX. No differences, so this 23/1998 Malay SL2S7 is really 100% locked!
The PII 333 SL2QF is the only unlocked Deschutes in my collection. Should be also good for old speed sensitive DOS Games. 400Mhz is the max. stable with 100MHz FSB, 450Mhz only a bootscreen (also with disabled L2 Cache), which is plausible for a earlier dA0 Deschutes core. The SL2S7 runs fine with 448Mhz (112MHz FSB).
A multiplier changing tool for DOS would be also interesting for a Pentium II Klamath/Deschutes. I know, not possible on the fly with this hardware. A CPU Soft Menu is the way to go.
NostalgicAslinger wrote on 2023-06-27, 18:13:A multiplier changing tool for DOS would be also interesting for a Pentium II Klamath/Deschutes. I know, not possible on the fly with this hardware. A CPU Soft Menu is the way to go.
The Pentium II/III signal lines for multiplier selection are only open for a few milliseconds at RESET. Once that brief period has passed (for the BIOS to make a choice), there is unfortunately no way to poke the CPU multiplier again.
(Pentium III mobiles introduced the SpeedStep feature, which allows a very limited multiplier selection at runtime. Bottom one being 6.0x IIRC.)
NostalgicAslinger wrote on 2023-06-27, 18:13:A CPU Soft Menu is the way to go.
Instead, Multiplier jumpers could be wired to a speed-selection case switch. Like a switch to toggle between 133 and 400 MHz
--> ISA Soundcard Overview // Doom MBF 2.04 // SetMul
Thanks for your infos! I use a Pentium MMX 233 or my AMD K6-III+ system for speed sensitive DOS Games with SETMUL. Pentium MMX is still my favourite for this. For my Slot 1 Celeron Mendocino sys, the tool "Throttle" (http://www.oldskool.org/pc/throttle/DOS) is the way to go. Works good, but on too lowest settings, I get jerks and sound dropouts.
Actually, it may not matter, but still I wonder why my SL2S7 has a lock. Maybe a Intel insider could help...🧐 and find out more.
gerwin wrote on 2023-06-27, 18:26:Instead, Multiplier jumpers could be wired to a speed-selection case switch. Like a switch to toggle between 133 and 400 MHz
Yes, a Slot 1 i440BX Mainboard with a CPU Soft Menu is the way to go, if you want a Pentium II Klamath/Deschutes build for speed flexibilitys. I recommend the Klamath less, because they put more stress on the VRM voltage converters. I have a unlocked PII Klamath 300, also a nice PII CPU (because this is the fastest version and was very expensive in 1997) but I would not use it for a Slot 1 DOS Gaming build, always prefer unlocked Deschutes.
PIII Speedstep is only 2 states as opposed to later ones that allowed fine grained multipliers to actively adjust performance to extend the battery life a bit. PIII have Low and standard multipliers. This depends on standard speed dictates the low.
PII does not have speedstep.
Look in this links.
https://www.thinkwiki.org/wiki/Intel_Mobile_Pentium_III
https://www.thinkwiki.org/wiki/Intel_Mobile_Pentium_III-M
Cheers,
Great Northern aka Canada.
Maybe an interesting locked Deschutes CPU: A Pentium II 350 SLU3 from 11 week/1999, Irland. This Deschutes CPU has the lowest multiplier of 3.5x. From 233 MHz until 466 MHz (66MHz FSB until 133MHz FSB). Also stable with 501MHz (143MHz FSB) at stock 2.00V voltage, the dB0 stepping makes ~500MHz possible.
A good compromise, because unlocked Deschutes are not so easy to find.
NostalgicAslinger wrote on 2023-06-28, 15:49:Maybe an interesting locked Deschutes CPU: A Pentium II 350 SLU3 from 11 week/1999, Irland. This Deschutes CPU has the lowest multiplier of 3.5x. From 233 MHz until 466 MHz (66MHz FSB until 133MHz FSB). Also stable with 501MHz (143MHz FSB) at stock 2.00V voltage, the dB0 stepping makes ~500MHz possible.
I would just choose Pentium III 533B/533EB over that. Yeah, multiplier is 4x, but I don't have to play the lottery to overclock.
Or just go straight to Klamath. All have unlocked multiplier and can be overclocked around 350Mhz.
I must be some kind of standard: the anonymous gangbanger of the 21st century.
Wouldn't a Klamath at 350 be pretty much winning the silicon lottery? Were they even made with cache chips capable of 175 MHz?
Please use the "quote" option if asking questions to what I write - it will really up the chances of me noticing 😀
Well, not sure about all Klamath, but PII 233 I have (1998 week 16) use identical L2 chips to PII 300 and can be overclocked slightly better. I think it's safe to say that all Klamath from 1998 are identical.
I must be some kind of standard: the anonymous gangbanger of the 21st century.
The only problem of the Klamath is the high TDP of 43W for the 300MHz model. I would always prefer a Deschutes 300 for the half of the power consumption of a same clocked Kamath = less stress for the components, voltage regulator on this old i440LX/BX mainboards.
I acquired a 350MHz Deschutes PII (SL2S6, 1998 week 43, Ireland) a few days ago and was very surprised to find that it has an unlocked multiplier. It's not a particularly remarkable overclocker- it runs stable at 400MHz (4 x 100), but crashes at 450MHz (4.5 x 100) shortly after loading the Windows 98 desktop.
Somewhat ironically, its fastest stable speed appears to be achievable using the stock multiplier, at 3.5 x 124 = 434MHz.
Other than the unusually late production date for an unlocked PII, this CPU performs much the same as my earlier unlocked Deschutes, a 333MHz version (SL2KA, 1998 week 01, Philippines).
MT-32 Editor- a timbre editor and patch librarian for Roland MT-32 compatible devices: https://github.com/sfryers/MT32Editor
sfryers wrote on 2023-12-28, 12:22:I acquired a 350MHz Deschutes PII (SL2S6, 1998 week 43, Ireland) a few days ago and was very surprised to find that it has an unlocked multiplier. It's not a particularly remarkable overclocker- it runs stable at 400MHz (4 x 100), but crashes at 450MHz (4.5 x 100) shortly after loading the Windows 98 desktop.
Somewhat ironically, its fastest stable speed appears to be achievable using the stock multiplier, at 3.5 x 124 = 434MHz.
Other than the unusually late production date for an unlocked PII, this CPU performs much the same as my earlier unlocked Deschutes, a 333MHz version (SL2KA, 1998 week 01, Philippines).
Would you mind trying if it takes 5x multiplier at 66MHz? It may be that the 350s came unlocked to be able to run at least 333 on an LX board?
Please use the "quote" option if asking questions to what I write - it will really up the chances of me noticing 😀
Yes, it will do 333Mhz at 66 x 5. I did get it to post at 366 (66 x 5.5) and 400 (66 x 6) as well, but haven't done any detailed testing of those configurations.
MT-32 Editor- a timbre editor and patch librarian for Roland MT-32 compatible devices: https://github.com/sfryers/MT32Editor
sfryers wrote on 2023-12-28, 13:36:Yes, it will do 333Mhz at 66 x 5. I did get it to post at 366 (66 x 5.5) and 400 (66 x 6) as well, but haven't done any detailed testing of those configurations.
Very, very interesting. I'm considering making a Frankenstein PII 500 at 5x100, using TAG and cache from a faster P!!! just for the hell of it, trying how the PII would perform at a faster speed. I suspect the cache more than the actual core to be the limiting factor ...
Please use the "quote" option if asking questions to what I write - it will really up the chances of me noticing 😀
Oh, darn it. The SL2KA isn't with ECC L2 cache, which it looks to be necessary for transplanting P3 cache to it ...
Please use the "quote" option if asking questions to what I write - it will really up the chances of me noticing 😀
