no.

OK, thanks, I feared as much.

C0deHunter wrote on 2021-04-14, 19:00:

OK, thanks, I feared as much.

What is the lowest speed SLOT 1 Pentium CPU that I can find, which is close to the original Socket7 speed?

I think you may be trying to solve a problem in a less efficient way.

As far as I was aware, the “best” solution for slowing down a relatively quick Slot 1 system would be using a VIA Nehemia or Ezra/Ezra-T Socket 370 CPU in a slocket adapter. This combined with turning caches on or off, and playing with SETMUL will allow you to have anywhere between ~66MHz and ~1.2GHz at your disposal.

Covington Celerons are pretty slow since they have no l2 cache. They perform at Pentium1 levels. I guess this is about Socket 7 speed.
But you could also just disable the l2 cache on a Pentium II for about the same effect.

I use SetMUL L1D, and L2D commands often, but I wanted a *permanent* hardware solution!

C0deHunter wrote on 2021-04-14, 19:12:

I use SetMUL L1D, and L2D commands often, but I wanted a *permanent* hardware solution!

Would a SLOT 1 PII-233~266 be close enough to the speeds?
Would any of the following be suitable?

https://www.ebay.com/itm/Intel-80522PX266512- … g0AAOSwa8dZwuKx

https://www.ebay.com/itm/Intel-Pentium-II-805 … r8AAOSw1oJdI0W1

https://www.ebay.com/itm/Intel-Pentium-II-805 … D8AAOSwaWhZwth6

https://www.ebay.com/itm/Intel-SL2HE-Pentium- … ~wAAOSwJU5d1FsS

Celeron 266 is the slowest slot 1 CPU that you could use.

Slowest Slot 1 CPU is Pentium II 233 Klamath (or maybe cacheless Celeron 266MHz) ?
Besides that, some SLOT1 cpus are multiplier unlocked. Lowest possible multiplier is 2x (automatically disabling L2 cache) or 2.5x with L2 enabled.
I have for example PII 400 SL2S7 which can be clocked 133Mhz (2x66 without L2) and 166Mhz(2.5x66MHz with L2) up to 5x100MHz stable.

zyga64 wrote on 2021-04-14, 19:19:

Slowest Slot 1 CPU is Pentium II 233 Klamath (or maybe cacheless Celeron 266MHz) ?

Depends on what you're throwing at it.

The Celeron 266 has the same core as the P2-333, just no L2 cache.

FPU-intensive stuff (Quake...) runs pretty well, only marginally slower than on a P2 at same clock,on par with a P2-233. On the other hand, ALU-intensive code tends to suffer badly. In MDK it is beaten by a P200MMX and only just scrapes ahead of a Winchip 2 233...

Besides that, some SLOT1 cpus are multiplier unlocked. Lowest possible multiplier is 2x (automatically disabling L2 cache) or 2.5x with L2 enabled.
I have for example PII 400 SL2S7 which can be clocked 133Mhz (2x66 without L2) and 166Mhz(2.5x66MHz with L2) up to 5x100MHz stable.

Yep. And you can always disable L2 cache on CPUs that have it. A P2-233 with L2 disabled is slower than the Celeron-266, not to mention one of the early Deschutes CPUs without multiplier lock.

As dionb and zyga64 said, the first PII's can be clocked at 2*66 or even 2*60 FSB on boards that still have FSB switches. The old PII's should be easier to find than the cacheless celerons.

Thanks! Which one of the eBay links do you recommend then?

https://www.ebay.com/itm/Intel-80522PX266512- … g0AAOSwa8dZwuKx

https://www.ebay.com/itm/Intel-Pentium-II-805 … r8AAOSw1oJdI0W1

https://www.ebay.com/itm/Intel-Pentium-II-805 … D8AAOSwaWhZwth6

https://www.ebay.com/itm/Intel-SL2HE-Pentium- … ~wAAOSwJU5d1FsS

I am about to order the one that you recommend as soon as possible!

paradigital wrote on 2021-04-14, 19:08:

I think you may be trying to solve a problem in a less efficient way.

As far as I was aware, the “best” solution for slowing down a relatively quick Slot 1 system would be using a VIA Nehemia or Ezra/Ezra-T Socket 370 CPU in a slocket adapter. This combined with turning caches on or off, and playing with SETMUL will allow you to have anywhere between ~66MHz and ~1.2GHz at your disposal.

Yep, I have a nehemiah processor. With enough creativity you can run it at any speed.

https://docs.google.com/spreadsheets/d/1usQPR … krWbcvbPaw/edit

Finding a good slotket adapter with the right jumpers is pretty hard though, but assuming you can, I highly recommend it.

I have decided to get this:

https://www.ebay.com/itm/HP-PII-233Mhz-512k-S … o1a8zY1&LH_FR=1

Nice, I'm a big fan on Pentium II's basically the same as a Pentium Pro machine without the thousand dollar price tag 😀

zyga64 wrote on 2021-04-14, 19:19:

Slowest Slot 1 CPU is Pentium II 233 Klamath (or maybe cacheless Celeron 266MHz) ?
Besides that, some SLOT1 cpus are multiplier unlocked. Lowest possible multiplier is 2x (automatically disabling L2 cache) or 2.5x with L2 enabled.
I have for example PII 400 SL2S7 which can be clocked 133Mhz (2x66 without L2) and 166Mhz(2.5x66MHz with L2) up to 5x100MHz stable.

That's nice, and being a Deschutes core, you must be able to almost run it on passive cooling at 133 MHz?

H3nrik V! wrote on 2021-04-15, 10:06:

zyga64 wrote on 2021-04-14, 19:19:

(...)
I have for example PII 400 SL2S7 which can be clocked 133Mhz (2x66 without L2) and 166Mhz(2.5x66MHz with L2) up to 5x100MHz stable.

That's nice, and being a Deschutes core, you must be able to almost run it on passive cooling at 133 MHz?

Probably yes, but I only tested it at this speed, and that's all. No serial use, because for playing with early DOS I prefer my 486DX33 machine.
In fact it has original BIG heatsink which I don't know how to remove 😀 It looks exactly like this one. link
I rather prefer smaller cooling solution from original Intel BOXed processor (those are quiet).
At its original frequency (400Mhz) passive heatink is definitely not sufficient. It's too hot in my opinion, so small fan is attached in addition.

Good thing is - the motherboard I use (rather uncommon Totem P2BX with Intel BX chipset) has jumper for 66/100MHz so FSB can be changed on the fly (tested by me)..

With good case airflow I run the P2-400 with its original gold-colored passive heatsink all day. I don't remember the temps ever going above 60C even under Prime95 stress test.

I just placed an order for this!

https://www.ebay.com/itm/HP-PII-233Mhz-512k-S … o1a8zY1&LH_FR=1

Judging by the screenshots of this CPU, this would be good fit for my need