I do not remember them being locked but it was near impossible to get a 512k or 1mb cache 200Mhz to run stable at 233 back in the day when I tried it. The 180mhz 256k could run stable at 200mhz but the gain was marginal. Have not overclocked a Pro processor in years so may be wrong about locked but do remember running a 200 512k at 220Mhz for a long while on a Asus board.

i mean unlocked for... underclock... 50Mhz*2=100Mhz, in poor 16 bit performance can be an interesting machine....

Yes, they are unlocked.

The overdrives are LOCKED.

Horun wrote on 2020-05-23, 21:56:

I do not remember them being locked but it was near impossible to get a 512k or 1mb cache 200Mhz to run stable at 233 back in the day when I tried it.

The internal L2 cache running at full speed certainly didn't help overclocking.

Very true. I've heard if you disable the L2, the chips will often overclock past 333mhz.

But without L2... Not exactly worth it.

Horun wrote on 2020-05-23, 21:56:

it was near impossible to get a 512k or 1mb cache 200Mhz to run stable at 233

No it's not and looking at http://valid.x86.fr/top-cpu/496e74656c2050656 … 0323333204d487a there is an ALR 6x6 (Unisys 10140) with 6 x 1MB P-Pros sunning at 233 MHz

red-ray wrote on 2020-05-24, 09:08:

Horun wrote on 2020-05-23, 21:56:

it was near impossible to get a 512k or 1mb cache 200Mhz to run stable at 233

No it's not and looking at http://valid.x86.fr/top-cpu/496e74656c2050656 … 0323333204d487a there is an ALR 6x6 (Unisys 10140) with 6 x 1MB P-Pros sunning at 233 MHz

I said "was near impossible", not totally impossible. If you notice #11 is just below 233mhz and 7 of those 10 that are 233 or higher are by the same person and there is no mention if they run stable, just a CPU-Z screen showing the speed.

Horun wrote on 2020-05-24, 14:29:

I said "was near impossible", not totally impossible. If you notice #11 is just below 233mhz and 7 of those 10 that are 233 or higher are by the same person and there is no mention if they run stable, just a CPU-Z screen showing the speed.

I found it very easy to get my 512KB cache PentiumPro 200 running at 233 MHz and the system is very stable. I just fired it up and generated the following screen shot along with a SIV save file. In general on unstable systems generating a SIV save file is rarely if ever possible.

This is the first time I have booted it since 2019-05-13 @ 09:17:22, I took it out of a box, booted it up and it "just worked" 😀

red-ray wrote on 2020-05-24, 18:09:

I found it very easy to get my 512KB cache PentiumPro 200 running at 233 MHz and the system is very stable. I just fired it up a […]
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Horun wrote on 2020-05-24, 14:29:

I said "was near impossible", not totally impossible. If you notice #11 is just below 233mhz and 7 of those 10 that are 233 or higher are by the same person and there is no mention if they run stable, just a CPU-Z screen showing the speed.

I found it very easy to get my 512KB cache PentiumPro 200 running at 233 MHz and the system is very stable. I just fired it up and generated the following screen shot along with a SIV save file. In general on unstable systems generating a SIV save file is rarely if ever possible.

This is the first time I have booted it since 2019-05-13 @ 09:17:22, I took it out of a box, booted it up and it "just worked" 😀

I see that you have installed xp, how does it work with 233mhz?

AlessandroB wrote on 2020-05-24, 18:38:

I see that you have installed xp, how does it work with 233mhz?

It's much the same as Windows 2000 provided you have enough memory. You really need at least 256MB which is what I had installed 12 months ago, but as you can see it does run walk with 128MB.

In terms of day to day use I don't really have a feel for it's usability as I use a rather OTT Core i9 system.

That is great ! You have a Step 9 sB1 P.Pro just like those top performers in your link so it might even clock a bit higher. I think the early stepping sA0 were the ones that had issues with overclocking, they were the first in the 180 and 200mhz released speeds. I have one sA0, the other is a sA1 stepping but only 256k cache, am fairly sure it could run at 233 but never tried it.

I've thought of trying to OC my 200MHz 200MHz chip to 233MHz but I don't know if my board can do it, I have...whatever Intel called their basic single Socket 8 board.

EvieSigma wrote on 2020-05-24, 21:10:

I've thought of trying to OC my 200MHz 200MHz chip to 233MHz but I don't know if my board can do it, I have...whatever Intel called their basic single Socket 8 board.

I suspect it's an Intel VS440FX which is often called Venus, this is the board I have running at 233 MHz. What stepping is your CPU, it seems that Stepping 9 [sB1] CPUs do better.

In general I found found most boards can do x3.5, but x4.0 is less common

All of my PPro 200 1MB run fine at 233. I have no idea about the steppings 🤣

kixs wrote on 2020-05-24, 22:10:

All of my PPro 200 1MB run fine at 233. I have no idea about the steppings 🤣

All PPro 200 1MB are Stepping 9 [sB1]

red-ray wrote on 2020-05-24, 21:38:

EvieSigma wrote on 2020-05-24, 21:10:

I've thought of trying to OC my 200MHz 200MHz chip to 233MHz but I don't know if my board can do it, I have...whatever Intel called their basic single Socket 8 board.

I suspect it's an Intel VS440FX which is often called Venus, this is the board I have running at 233 MHz. What stepping is your CPU, it seems that Stepping 9 [sB1] CPUs do better.

In general I found found most boards can do x3.5, but x4.0 is less common

I dunno, it's a 200MHz/256k cache CPU but I don't know if there were multiple steppings of the 256k variant.

EvieSigma wrote on 2020-05-24, 22:23:

I dunno, it's a 200MHz/256k cache CPU but I don't know if there were multiple steppings of the 256k variant.

There are multiple stepping's, why don't run my SIV utility and check the stepping?

If you have NT4/W2K/WXP running SIV should also report which motherboard you have.

Yes there are 3 stepping for the 200Mhz 256k cache plus more than a few ES/Q, and 11 s-spec versions thru those 3 steppings. Yes SIV will tell you. I think the Intel VS440FX Venus is a good board, so is Asus P6NP5. A few of the OEM variants (a Compaq board comes to mind, I have one) are pitiful with respect to jumpers and features. The Compaq will puke if trying to OC, the Asus is fairly good so is Venus. Have actually been looking for another Soc8 board since there are a few spare 200/256k sitting in my drawer....

The ALR 6x6 system mentioned above is described at http://www.cpushack.com/2019/01/12/mini-mainf … rver-from-1997/

Part 4 of that article describes overclocking. 6 x 200 MHz 1MB were tested and ran at 233 MHz. 6 x 200 MHz 256KB ran at both 233 and 240. It's a well written article (as is normal for the guest writer on CPUShack) and well worth the read. A later article describes the same system with 6 x PII OD 😀