I think I looked into the P100+ a number of years ago, but couldn't find anyone that actually had one in their collection.
Are there any Pentium boards that support a 45MHz FSB?

I looked on a few sites, and can find no evidence of them existing.

debs3759 wrote on 2024-06-06, 17:14:

I looked on a few sites, and can find no evidence of them existing.

I’m wondering if it’s a case that nobody wanted to support the bus speed so it got deprecated at the last minute. I’m honestly very surprised the 80mhz pr90 released considering how few boards had that FSB, though admittedly I had a few early socket 5 boards (made before the 6x86) that had an undocumented 40mhz FSB .

Lots of Cyrix data included that speed grade including reviews and manuals but Im guessing it got dropped similar to Cyrix trying to release 90mhz FSB chips but only 1 motherboard supported that FSB.

I don’t believe I have encountered one.

You reminded me of something btw, Little off topic but kinda related, many of the cyrix chips have a 1x multiplier setting. It eventually disappeared with the 2.2v chips. And the max some supported was 4x

There are also some motherboards that supported, what was it?, 7mhz fsb option. They weren’t common, but there was at least one.

So the slowest cyrix you can get for socket 5/7 would in theory be able to run less than 10 mhz, but I don’t recall anyone doing this yet.

Let it be known, the challenge is put forth, does anyone accept the challenge?

Edit:
Socket 5/7 underclock! Aiming for the abyss!

I don't know how many bus speeds could be jumpered on a typical Socket 5/7 motherboard, but maybe there just wasn't enough room in the design to squeeze in a 45MHz setting if 40 and 55MHz were already on the menu.

Maybe it was an embedded industrial type part? Something directly soldered onto an embedded board that supported the weird FSB?

Got a vague recollection of reading in a magazine sometime around 96ish that it was presumed that those were parts intended for South American and poorer parts of Asia markets and weren't expected to turn up in Europe or North America. Certainly it wasn't long at all before the computer fairs had the PR133 at 10 UK pounds and the PR166 at 20. That seemed absurdly cheap enough that it wouldn't be worth shipping anything slower. So if a case or two did slip in, they probably didn't re-order, availability of maybe a month.

BitWrangler wrote on 2024-06-07, 03:38:

Got a vague recollection of reading in a magazine sometime around 96ish that it was presumed that those were parts intended for South American and poorer parts of Asia markets and weren't expected to turn up in Europe or North America. Certainly it wasn't long at all before the computer fairs had the PR133 at 10 UK pounds and the PR166 at 20. That seemed absurdly cheap enough that it wouldn't be worth shipping anything slower. So if a case or two did slip in, they probably didn't re-order, availability of maybe a month.

Oh I remember the Cyrix chip going from almost the same price as a Pentium in the higher clocks to stupid cheap I bought one directly after big price drops that happened in a few months.

My guess is that the really slow PR90/PR120 were really only relevant during the pre launch period and the October 1995 launch date.

I eventually needed 2 PCs for our business “expanding “ after a short period of time and bought a PR200 rather soon after its launch ~96,
(considered a 6x86 instead of the 5x86 I ordered earlier in October/November 95 but found nobody had stock)
I attempted to order a ST6x86 pr120 at that point after the pr200 launch instead because it was listed at a give away price but they immediately told me they didn’t have a pr120 part arrive in months and believed they were out of production, the slowest with stock was a pr166, I ended up with an IBM pr200 because it wasn’t that much more. Funny thing was all the slowest 6x86 chips I encountered were sold as ST branded chips, mid and upper ranger were sold as Cyrix or IBM, with the IBM demanding a small premium over ST and Cyrix branded.

Lots of commentary back and forth of you would be stupid not to buy Cyrix back in yeah olde times strictly due to price

https://groups.google.com/g/comp.sys.ibm.pc.g … n/c/dtrupvl11tk

Seems like my rather modest pr200 system was a $399 affair until I added a cd-drive later. Worked much better than the dx2 it replaced and oddly it was just as cheap as the 5x86 I bought not even a year earlier but with much better specs.

Things changed very fast back then.

I also believe Cyrix sold immense numbers of their slower Chips in Europe for some reason over the US because fellow Cyrix people I encountered online at that point were all European for some reason, US guys were all extremely enamored by Quake even early in 96 becoming enraged by the poor Cyrix vrs quake performance.

The funny part was even folks who had an early socket 5 motherboard a P90 and mediocre cache/ram with a mediocre video card had crap experiences running Quake as well

I remember this PR / performance rating on national television, being prime time news in the Netherlands. That people must not be fooled about the Intel 200 MHz = PR200+ story.

rmay635703 wrote on 2024-06-10, 12:37:

Oh I remember the Cyrix chip going from almost the same price as a Pentium in the higher clocks to stupid cheap I bought one dir […]
Show full quote

BitWrangler wrote on 2024-06-07, 03:38:

Got a vague recollection of reading in a magazine sometime around 96ish that it was presumed that those were parts intended for South American and poorer parts of Asia markets and weren't expected to turn up in Europe or North America. Certainly it wasn't long at all before the computer fairs had the PR133 at 10 UK pounds and the PR166 at 20. That seemed absurdly cheap enough that it wouldn't be worth shipping anything slower. So if a case or two did slip in, they probably didn't re-order, availability of maybe a month.

Oh I remember the Cyrix chip going from almost the same price as a Pentium in the higher clocks to stupid cheap I bought one directly after big price drops that happened in a few months.

My guess is that the really slow PR90/PR120 were really only relevant during the pre launch period and the October 1995 launch date.

I eventually needed 2 PCs for our business “expanding “ after a short period of time and bought a PR200 rather soon after its launch ~96,
(considered a 6x86 instead of the 5x86 I ordered earlier in October/November 95 but found nobody had stock)
I attempted to order a ST6x86 pr120 at that point after the pr200 launch instead because it was listed at a give away price but they immediately told me they didn’t have a pr120 part arrive in months and believed they were out of production, the slowest with stock was a pr166, I ended up with an IBM pr200 because it wasn’t that much more. Funny thing was all the slowest 6x86 chips I encountered were sold as ST branded chips, mid and upper ranger were sold as Cyrix or IBM, with the IBM demanding a small premium over ST and Cyrix branded.

Lots of commentary back and forth of you would be stupid not to buy Cyrix back in yeah olde times strictly due to price

https://groups.google.com/g/comp.sys.ibm.pc.g … n/c/dtrupvl11tk

Seems like my rather modest pr200 system was a $399 affair until I added a cd-drive later. Worked much better than the dx2 it replaced and oddly it was just as cheap as the 5x86 I bought not even a year earlier but with much better specs.

Things changed very fast back then.

I also believe Cyrix sold immense numbers of their slower Chips in Europe for some reason over the US because fellow Cyrix people I encountered online at that point were all European for some reason, US guys were all extremely enamored by Quake even early in 96 becoming enraged by the poor Cyrix vrs quake performance.

The funny part was even folks who had an early socket 5 motherboard a P90 and mediocre cache/ram with a mediocre video card had crap experiences running Quake as well

Yeah I don't think people these days appreciate the sheer amount of "Leave it or insert it in the ad copy because maybe we'll get some in the month or so before it prints." that went on. Leading to a lot of vaporware at both ends in the no longer available and not quite yet available categories. So you see scans of old computer mags and say "Wow you could get X thing for Y money on Z date.." umm yeah, middle of the road stuff mature in the market but not too mature, maybe, everything else, 70:30 shot. Even on the internet before the days of live store inventories, pricelist/website might be listing things they don't actually have. Though I wonder if by then they were playing games, listing "benchmark" items cheap, while not having them, so ppl were thinking the rest of their prices were really good without actually checking. I know Pricewatch had to get mad with everyone a few of times back in the day because of crap like that, threaten delisting for all their stuff.

Anyway, I haven't seen a Cyrix PR120/100Mhz lately, or maybe at all, foggy memory, but do have an IBM one here.

IMO you bested the "Quake frames per dollar" than Intel often anyway, might need the PR-200 to beat a Pentium 133, but it was maybe $5 cheaper.

Edit: just thinking there might be some gaming of consumer psychology going on either directly from Cyrix, in the channel, or at retail, where people go not for the very cheapest thing, but the second cheapest, or more towards the middle of the range. Thus the very cheapest thing does not sell in any numbers anyway, the second cheapest sells really well, so why bother actually having the very cheapest in stock?

I was looking at my collection this morning, but had forgot about this post. I believe I found a pr100 6x86 but it was a 100mhz not a 90mhz. Does that make any sense? 🤔

Are you certain it was a PR100 and not a 100GP?
I kind of doubt it would be a "PR"100, because I'm pretty sure the change from "P"to "PR" didn't happen until late '96 or early '97. If a P100+ were to actually exist, it likely would have been fairly early on just after the adoption of the "P" rating system, and likely would have had a very short production run. I didn't even know "PR" classic 6x86s existed until years later. I figured that only affected the 6x86L.

BitWrangler wrote on 2024-06-10, 18:13:

Edit: just thinking there might be some gaming of consumer psychology going on either directly from Cyrix, in the channel, or at retail, where people go not for the very cheapest thing, but the second cheapest, or more towards the middle of the range. Thus the very cheapest thing does not sell in any numbers anyway, the second cheapest sells really well, so why bother actually having the very cheapest in stock?

Probably the same psychology used when pricing beverages at restaurants. People tend to always choose the "medium" sized ...

Anonymous Coward wrote on 2024-06-11, 13:33:

Are you certain it was a PR100 and not a 100GP?
I kind of doubt it would be a "PR"100, because I'm pretty sure the change from "P"to "PR" didn't happen until late '96 or early '97. If a P100+ were to actually exist, it likely would have been fairly early on just after the adoption of the "P" rating system, and likely would have had a very short production run. I didn't even know "PR" classic 6x86s existed until years later. I figured that only affected the 6x86L.

No, I may have mispoke but it had some kinda 100 rating, and 100 mhz from my recall. I can check when I get home

Unfortunately the silk is damaged 🙁

The silkscreen is damaged, but enough of it exists to say for certain it's not a P100+GP. It's a 100GP, and it's rated for 100MHz.
Not sure it was really worth it for Cyrix to ruin their credibility with the "P/PR" ratings, but I guess either way it wouldn't have stopped them from going out of business.

There are certainly some 90 MHz in collections, but only marked as 90 MHz, not P100 or PR100

debs3759 wrote on 2024-06-12, 15:23:

There are certainly some 90 MHz in collections, but only marked as 90 MHz, not P100 or PR100

I wonder what motherboard would ever work with those?

The PCCHIPS m590 is the only motherboard that had a 90mhz FSB and I’ve never seen 45mhz FSB in the wild.

What I do find strange is the sheer number of Cyrix chips that were floating around before the official launch date even back in ye olde times.

I actually thought they were available before they really were because of the groups I hung out on discussing the chips , must have sent them out to magazines and board makers or something.

rmay635703 wrote on 2024-06-12, 18:43:

I wonder what motherboard would ever work with those? […]
Show full quote

debs3759 wrote on 2024-06-12, 15:23:

There are certainly some 90 MHz in collections, but only marked as 90 MHz, not P100 or PR100

I wonder what motherboard would ever work with those?

The PCCHIPS m590 is the only motherboard that had a 90mhz FSB and I’ve never seen 45mhz FSB in the wild.

What I do find strange is the sheer number of Cyrix chips that were floating around before the official launch date even back in ye olde times.

I actually thought they were available before they really were because of the groups I hung out on discussing the chips , must have sent them out to magazines and board makers or something.

60x1.5
90x1
45x2

Some cyrix chips supported 1x but Idk if that one did.

Many around that time, only had bf0 so only two multiplier options. Which was usually 1.5 and 2x. I’m basing this on other chips, I really haven’t messed with these slower cyrix chips much. So feel free to correct. But motherboatds of that time usually had only bf0

bf1 came along around 133-166 era

Bf2 intel and bf2 amd/cyrix (different pins) came along around the 233-266 era.

Technically, it is possible to have 4 settings with one register. Pull down, pull up, floating. And a forth if you tie it to a modulating signal. Some 486 chips did this for setting I think 2 or 2.5x I think it was dx4? Tying it to breq? Signal? Trying to remember. (Don’t quote)

Anyway, having only one register suggests only 2 multiplier settings. And only 2 were typical for socket 5