Possible for a laptop to be compatible with a Pentium II and III at the same time?

[kfzhu1229]

So the story begins after I have fixed a broken 750Mhz Pentium III MMC2 CPU by replacing the ADP3420 chip shorting the CPU voltage to ground.
About a few weeks ago that CPU got sold on eBay. Worried that the buyer has no idea what he is doing and potentially giving me a negative feedback and all sorts of hassle, I asked him/her whether he knows exactly what he is doing and what is his intended use for the processor.
To that he responded he has a Dell Inspiron 7500 with a Celeron 466 and is intending to upgrade the CPU to this one. Seeing the Celeron 466 clearly belonging to the Dixon family of processors with just 66Mhz FSB, I thought surely the laptop won't even post with this processor, especially with the fact that that thing is an award winning budget conscious model and it came with a very very basic BIOS. But upon googling I have seen such models with Pentium III 650 processors so I responded it might work but I made it clear I can't do any returns for incompatibility.
Just yesterday I got a positive feedback claiming that the processor worked perfectly. And by the looks of it he didn't even need the 2KOhm resistor mod to get 750Mhz working on that thing!
So this made me think that laptops that work with both MMC2 PII's and PIII's really do exist. So does this mean that you can potentially put a Pentium II CPU in a ThinkPad 600X or 390X for example?

[cadillacmike68]

Interesting, but who would want to put a P II in a 600X that will probably already have a P III in it??

[Thinkpad4by3]

FWIW I believe that Putting P3 chips in a 770X was common, and that was a P2 machine with the MMC2 socket. If it can go forward, I see no reason it can't go back as well. On a more modern note, T420 could take a 3rd gen processor and same for the T430 for the 2nd gen. Should be okay to go ahead.

[kfzhu1229]

FWIW I believe that Putting P3 chips in a 770X was common, and that was a P2 machine with the MMC2 socket. If it can go forward, I see no reason it can't go back as well. On a more modern note, T420 could take a 3rd gen processor and same for the T430 for the 2nd gen. Should be okay to go ahead.

Hmm I didn't know you can put Pentium IIIs in the likes of a 770X or a 600E. Persumably you might need a BIOS mod too.
What was even more interesting with that Inspiron 7500 is that not only did the CPU work out of the box, the speedstep worked too! This can't be an older chipset for sure as you can't just mod the BIOS to get speedstep working. What leads me to believe was that he has one of the later Inspiron 7500's with a newer board but a low end one means it came equipped with last gen low end technology? The Celeron 466 is a Dixon Pentium II Celeron for sure.
As for the case with sandy bridge vs ivy bridge, I thought the Intel's chipsets locked you out from putting an Ivy bridge CPU in a Sandy bridge motherboard? I know the other way around works out of the box as my T530 came with a Sandy bridge i3 which I later upgraded to i5-2520m and then i7-3720QM.

[Thinkpad4by3]

Ah I didn't know about the T420 Ivy-lock. Oh well .

Anyway thats possible, given the speed at which CPUs were progressing at that point, it was likely easier to grab a new chipset and throw some older hand-me-down CPUs in it and call it a consumer machine.

[kfzhu1229]

Anyway thats possible, given the speed at which CPUs were progressing at that point, it was likely easier to grab a new chipset and throw some older hand-me-down CPUs in it and call it a consumer machine.

Well I guess that is also my analogy with what Dell did too. I had a Latitude CPx J laptop which is the equivalent of a 600X with speedstep enabled. Putting a 450 or 500Mhz Pentium III CPU inside and the splash screen immediately changed to Latitude CPt V series. The model CPt is reserved by Dell for "budget conscious users" (or a fancy way of saying Latitude CPx models but contain Celerons, and this is way before the real low end Latitudes and Vostros were introduced) so I guess that makes sense.

[axur-delmeria]

As for the case with sandy bridge vs ivy bridge, I thought the Intel's chipsets locked you out from putting an Ivy bridge CPU in a Sandy bridge motherboard? I know the other way around works out of the box as my T530 came with a Sandy bridge i3 which I later upgraded to i5-2520m and then i7-3720QM.

It's not a chipset lock but a BIOS issue. Ivy Bridge CPUs have a different low-level initialization routine (IIRC it's for the on-die graphics), and Sandy Bridge-era Thinkpads don't know about it. There's no way to add it because Intel made it impossible to add CPU support tables to the BIOS after the Core 2 era-- I think they cryptographically signed the table itself.

One would have needed to pay Lenovo untold amounts of money just to convince them to add Ivy Bridge support for Sandy Bridge Thinkpads. But now we don't need to because of Coreboot.