Most of the P60 should also run well with 66MHz?
Default VCore of the 66MHz version is 5.15V and 5.00V for the 60MHz Pentium.
Also the Socket 4 mainboard must support the overvoltage settings.

NostalgicAslinger wrote on 2024-03-06, 12:58:

Also the Socket 4 mainboard must support the overvoltage settings.

Socket 4 mobos don't even have VRMs.

Trashbytes wrote on 2024-03-06, 01:52:

douglar wrote on 2024-03-06, 01:31:

Socket 4 was a relatively short lived and had strong competition from Socket 3 and Socket 5 for its entire run. The fdiv bug di […]
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BitWrangler wrote on 2024-03-05, 14:41:

In 93 and 94 maybe, many more P60 selling... but then I wonder if they had a glut of P66 and they got sold off cheap enough for a lot of people with 60 to spring for a 66 in 95 or so, putting a lot of P60s on shelves, and then again when the Socket 4 overdrive came out. Because I think the production of socket 4 motherboards tanked real quick so there were not a lot of opportunity for the P60s sitting idle to be soaked up. I think there ended up a glut of the overdrives too, there was some point late 90s where I was actually looking for a socket 4 board cheap because I could get hold of an overdrive for peanuts... a couple of years later when I landed a socket 4 system for pocket change at a yard sale all the overdrives had "gone away" again.

Socket 4 was a relatively short lived and had strong competition from Socket 3 and Socket 5 for its entire run. The fdiv bug didn’t help either. I think it’s getting hard to find the boards.

That reminds me about socket 6. I’ve never seen one.

Does anyone here have a socket 6 486 cpu?

From what I can find all socket 6 did was add two more pins to socket 3 and it was only meant for the DX4/DX4 Overdrive 3.3v CPUs, my guess was Intel doing Intel things again and solving problems that didnt exist and they had to create to sell boards.

Thank GOD the other fabs just ignored it, Intel at that time did some boneheadded things in an attempt to force other fabs off their platforms.

Officially socket 6 was for the 486dx4 to unreleased Pentium dx4 overdrive .

Intel released p24t too late and nobody was interested in 486 at that point so the official 100mhz+ p24t for dx4 systems never released

overdrive333 wrote on 2024-03-07, 21:42:

NostalgicAslinger wrote on 2024-03-06, 12:58:

Also the Socket 4 mainboard must support the overvoltage settings.

Socket 4 mobos don't even have VRMs.

Yes in a way, boards that is made to support Pentium 66 came with overvoltage VRM that boosted 5V to bit higher to make 66MHz to work.

Cheers,

Is this the DX2-40 some of you were looking for here (and some other Cyrix)?

https://www.ebay.fr/itm/256439518717

I believe intel also made a DX/2-40, but I think it was only a laptop verison.
Then there's the Overdrive for SX-20s, which is also effectively a DX/2-40.

Anonymous Coward wrote on 2024-03-12, 01:38:

I believe intel also made a DX/2-40, but I think it was only a laptop verison.
Then there's the Overdrive for SX-20s, which is also effectively a DX/2-40.

They certainly did. And yes, it was probably only used in laptops. Definitely one on my want-list!

Interesting thought with the Overdrive. Yes, it actually effectively is a DX2-40. It's just not as cool as having the "real deal" though ...

H3nrik V! wrote on 2024-03-12, 05:05:

Anonymous Coward wrote on 2024-03-12, 01:38:

I believe intel also made a DX/2-40, but I think it was only a laptop verison.
Then there's the Overdrive for SX-20s, which is also effectively a DX/2-40.

They certainly did. And yes, it was probably only used in laptops. Definitely one on my want-list!

Interesting thought with the Overdrive. Yes, it actually effectively is a DX2-40. It's just not as cool as having the "real deal" though ...

I have a 486 DX-50, I think Cyrix also made a DX-50 but all I find is the DX-40.

Trashbytes wrote on 2024-03-12, 05:27:

H3nrik V! wrote on 2024-03-12, 05:05:

Anonymous Coward wrote on 2024-03-12, 01:38:

I believe intel also made a DX/2-40, but I think it was only a laptop verison.
Then there's the Overdrive for SX-20s, which is also effectively a DX/2-40.

They certainly did. And yes, it was probably only used in laptops. Definitely one on my want-list!

Interesting thought with the Overdrive. Yes, it actually effectively is a DX2-40. It's just not as cool as having the "real deal" though ...

I have a 486 DX-50, I think Cyrix also made a DX-50 but all I find is the DX-40.

https://www.x86-guide.net/en/cpu/Intel-486DX2 … cpu-no2114.html

In 1992 after the DX/2 and VLB came out, very few people bothered with the DX-50. It kind of boggles the mind that somebody at Cyrix thought releasing a DX-50 clone in late 1993 was a good idea.

NostalgicAslinger wrote on 2024-03-06, 12:58:

Most of the P60 should also run well with 66MHz?
Default VCore of the 66MHz version is 5.15V and 5.00V for the 60MHz Pentium.
Also the Socket 4 mainboard must support the overvoltage settings.

All P60 cpus that I have tested worked at 66mhz without a voltage raise(no matter if the VRM section was installed or not).

What other 486 did IBM produce under license from Intel? I've got one DX2-66 with no S-Spec just IBM FRU, and IBM plant code, just wondering if there's an actually rare DX50.

I’d like to suggest an unusual entry for this: the PDP 1. Only 53 were ever made. Although another pdp model may possibly be more rare, the 1 has the additional distinction of being the first making it arguably also desirable to a collector.

Anonymous Coward wrote on 2024-03-12, 08:42:

In 1992 after the DX/2 and VLB came out, very few people bothered with the DX-50. It kind of boggles the mind that somebody at Cyrix thought releasing a DX-50 clone in late 1993 was a good idea.

Technically the DX-50 with its 50Mhz FSB should be faster than the DX2 which has a slower FSB double clocked, I guess the question then becomes does VLB support 50Mhz FSB without issues. I doubt many VLB boards could handle 50MHz FSB without stability issues and perhaps this alone is the reason the DX2 with a 33Mhz FSB was the popular choice as it synced perfectly with the VLB.

https://dfarq.homeip.net/486dx-50-versus-dx2/

Pretty much sums up, why the dx2 got so more popular than the dx50.

H3nrik V! wrote on 2024-03-13, 05:02:

https://dfarq.homeip.net/486dx-50-versus-dx2/

Pretty much sums up, why the dx2 got so more popular than the dx50.

Pretty much as I suspected, VLB was the main factor. A clock doubled DX4-100 does sound like it would be an interesting CPU to test with, I have a few DX4 100 Cpus I wonder if they would be fine with some testing on PCI only 486 boards at 50 FSB.

What about the Athlon 1400 Thunderbird, with a 100 MHz FSB (serial A1400AMS3B, not C which is the 133 MHz FSB one)? I’m having a headache finding one and it was an old dream as I wanted to update my motherboard at its best when I was younger (an old Abit KT7, not KT7A).
I know it’s a mass product but only a few found their way through their client, I believe, as the 133-MHz chipsets and the high-clock Duron arrived at the same time.

harddrivespin wrote on 2017-12-17, 16:27:

Just something interesting to think about- I know that the Cx5x86 120mhz is fairly rare, and that the Cx5x86 133mhz is far rarer (not sure if it made it out of the prototype stage) and the Intel TQ80486DX4100, which was a i486DX4-100 made for the military and one is known to exist. Any thoughts/ideas?

X5-150 P75+

kobaspaladin wrote on 2024-03-13, 12:09:

harddrivespin wrote on 2017-12-17, 16:27:

Just something interesting to think about- I know that the Cx5x86 120mhz is fairly rare, and that the Cx5x86 133mhz is far rarer (not sure if it made it out of the prototype stage) and the Intel TQ80486DX4100, which was a i486DX4-100 made for the military and one is known to exist. Any thoughts/ideas?

X5-150 P75+

AMD 5x86-P100 (Could possibly be p90)
AMD-X5-160ADZ

Apparently they do exist, not actually seen one myself.

amadeus777999 wrote on 2024-03-12, 09:39:

All P60 cpus that I have tested worked at 66mhz without a voltage raise(no matter if the VRM section was installed or not).

Thanks for the info! So the yield quality was not so bad for the P5 core.
Maybe the very eralier ones with the FDIV Bug need more voltage with 66MHz, because it was reported again and again how bad the yield rate was with the first Pentium...
It is actually nonsensical that 5.15V is then required for 66MHz clock, because the waste heat of the P5 is not that low either.