The Top 5 Worst CPUs of All Time @ [H]

Trimlock

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I would have to say early Pentium chips with the FDIV bug and/or the f00f bug were probably the worst. Think about it, we're talking about a CPU that screws up floating point calculations due to a design flaw and can be locked up to the point of requiring a physical reboot with one malicious instruction. I stuck with 486 chips until the Pentium II era.

https://en.wikipedia.org/wiki/Pentium_FDIV_bug
https://en.wikipedia.org/wiki/Pentium_F00F_bug
I switched at the MMX era, not because of the bug (it was fixed prior to that) but because then OEM prices were falling.
 

Keljian

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Sorry, I'll stop shouting.

Thankyou


Fair, but the "broken" protected mode switch didn't matter for consumers, who couldn't scrounge the memory for a multi-tasking protected mode operating system until the 1990s. And that point, the antiquated 16MB memory limit and the lack of virtual x86 mode made it tough to use.

Except that it ushered in the world of BBSes, the precursor to live messaging on the internet (including things like irc). - see my following response

The first *successful* use of the 286 MMU was Novell Netware in 1986, a system that would not be affected by the switch issues (being a server and all). Consumer experiences using OS/2 were poor because memory was too expensive for consumers.

No. The first successful consumer/prosumer use was software called Desqview by Quarterdeck I know because my neighbour who had one of those "rare as hen's teeth" C'T 286s was running it daily. This allowed for multiline BBSes. Memory wasn't the issue. In July 1985 the Amiga had a multitasking OS in 1.5 meg of ram. My family's XT (NEC V20) had 1 meg of ram - it was accessible to the average consumer

if the 286 had not been twice as fast as it's predecessor, it would have been a failure even if they had protected mode working perfectly. That massive performance increase is half the reason companies started to build servers around the 286! To me that's the very definition of a "check box" feature - useable enough for developers to get their feet wet (and start moving the industry forward), but not useful for the mainstream.

I'd put the 286 protected mode in the same class as Haswell's AVX2 Gather. the (future accelerated) instruction has the potential to revolutionize auto-vectorizing compilers everywhere, but the first generation has no hardware support.

The NEC V20 (and subsequent V30) were much faster than the 8086/8080/8008 - 30% clock for clock and twice the clock speed. This was a drop in replacement for the 8088 and was available in 1982. Some NEC V20s even got to 16Mhz and outran 286s.

Granted speed is always nice. The Pentium was a huge step up from the 486 for consumers, speed wise due to having two ALUs. The slot A Athlon was a huge leap forward from what had come before as it was psuedo risc and could handle even more data on the fly. The MediaGX (in all it's disgustingness) was revolutionary because it included a graphics hardware and audio hardware on the cpu.

I guess what I'm saying is there are many advances in many areas over the last 30 years.
 
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Keljian

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I would have to say early Pentium chips with the FDIV bug and/or the f00f bug were probably the worst. Think about it, we're talking about a CPU that screws up floating point calculations due to a design flaw and can be locked up to the point of requiring a physical reboot with one malicious instruction. I stuck with 486 chips until the Pentium II era.

https://en.wikipedia.org/wiki/Pentium_FDIV_bug
https://en.wikipedia.org/wiki/Pentium_F00F_bug

Yeah but nearly all processors out there have similar “bugs” as the F00F - https://en.m.wikipedia.org/wiki/Halt_and_Catch_Fire

The Pentium was revolutionary because it had two ALUs.
 

Keljian

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Make it simple: Cyrix ||| (Joshua core)

There was nothing inherently wrong with the Cyrix III - just that it was released much later than it should have been and they were trying to push the limits of an older architecture. It was a 486 in a pentium/super socket 7 chip.
 
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Dan_D

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There was nothing inherently wrong with the Cyrix III - just that it was released much later than it should have been and they were trying to push the limits of an older architecture. It was a 486 in a pentium/super socket 7 chip.

Not even close. Nothing Cyrix built or designed fits that description from its 5x86 onward. It implemented Pentium type features and used s 486 motherboard. The 6x86 on up had more in common with a Pentium or Pentium Pro than a 486.

AMD's 5x86 was pretty much a fast 486, but used a 486 motherboard. In fact no chip I'm aware of used a Pentium P54c or P55c socket with a 486-like architecture.

You might be thinking of the fact that the Cyrix III was only compatible with 486 type (I think FPU only) instructions. That was a post VIA design.
 

Keljian

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Not even close. Nothing Cyrix built or designed fits that description from its 5x86 onward. It implemented Pentium type features and used s 486 motherboard. The 6x86 on up had more in common with a Pentium or Pentium Pro than a 486.

AMD's 5x86 was pretty much a fast 486, but used a 486 motherboard. In fact no chip I'm aware of used a Pentium P54c or P55c socket with a 486-like architecture.

You might be thinking of the fact that the Cyrix III was only compatible with 486 type (I think FPU only) instructions. That was a post VIA design.

The Cyrix 3 was a butchered version of an updated Winchip, by Centaur, who were acquired by VIA. The design methodology and processor structure were very much 486esque rather than Pentium style, with a single pipeline and simplified design, even compared with the 6x86. Due to cost cutting, none of the fancy things which were slated to be implemented were.
 

Dan_D

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The Cyrix 3 was a butchered version of an updated Winchip, by Centaur, who were acquired by VIA. The design methodology and processor structure were very much 486esque rather than Pentium style, with a single pipeline and simplified design, even compared with the 6x86. Due to cost cutting, none of the fancy things which were slated to be implemented were.

That wasn't Joshua, that was Samuel if I remember correctly. Both were "Cyrix III" CPU's.
 

Keljian

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The issue with these wasn't the processor - it was the chipset. Often these were paired with via chipsets which, quite frankly, were full of bugs. ALI chipsets weren't that much better, but they worked.

http://www.philscomputerlab.com/dfi-k6xv366.html - I had one of these. It was a horrid thing, coming from an intel VX motherboard with an earlier k6 in it

Been looking for the C&T 286 online.. haven't found it yet..
 

cdr_74_premium

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I love crap =D

I was relatively well-known in my town for being able to make those PcChips boards running Pentium IIs perform reasonably well using a trickery of drivers and modded BIOSes and proper cooling.

I don't think I've even seen a RAMBUS module. They were so insanely overpriced, all retailers in my country just went straight for the Via chipsets. I had a PhD in 4in1 Driver behavior LOL.

Those were the days... today everything just works =D
 

Trimlock

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I love crap =D

I was relatively well-known in my town for being able to make those PcChips boards running Pentium IIs perform reasonably well using a trickery of drivers and modded BIOSes and proper cooling.

I don't think I've even seen a RAMBUS module. They were so insanely overpriced, all retailers in my country just went straight for the Via chipsets. I had a PhD in 4in1 Driver behavior LOL.

Those were the days... today everything just works =D
As simple as 4-in-one drivers were I hated them. Had to find which was had the right Realtek driver for either sound, nic or both!
 

Dan_D

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Via chipsets... *shudder*.

Glad those days are behind us, at least.

I've worked with a lot of systems and different chipsets over the years. I've probably worked with everything available chipset over the last two decades and even some crap predating that which were hold overs into the early days of my career servicing PC's and servers in different environments. VIA chipsets were consistently, far and away the worst I'd ever had to deal with. That said, the issues with VIA chipsets were usually driver related or the issues with the system were caused by other problems with the motherboard that were bigger than the shitty chipsets and their associated drivers.
 

Dan_D

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VIA wasn't bad for me, IMO it was SIS.

I had to work on a couple systems with SIS chipsets that were fucking terrible. However, in my experience VIA was consistently worse. Then again, SIS was rarer to encounter in my experience so that may have something to do with it.
 

DuronBurgerMan

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I had to work on a couple systems with SIS chipsets that were fucking terrible. However, in my experience VIA was consistently worse. Then again, SIS was rarer to encounter in my experience so that may have something to do with it.

If SIS was worse than VIA, I'm certainly glad I never touched that crap.
 

CAD4466HK

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If SIS was worse than VIA, I'm certainly glad I never touched that crap.

In my experience SiS was way worse than VIA. I dealt with plenty of budget Abit, EpoX and PC Chips/ECS mobos during the Super 7 and S370 era with garbage SiS chipsets.
But the ones that really set me on edge, were the 315/315E and the super shitty 320 (Xabre 80) and 330 (Mirage) chipsets. Another one was the PC Chips mobos with the soldered Durons and the 740 chipsets. Oh the humanity!

I don't miss SiS one fucking bit.
 

EchoWars

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My first 'modern' system was a PC Chips board with an SIS chipset (I didn't know any better). Much cursing and gnashing of teeth followed.

Had several VIA-based boards after that. By comparison, they were a fuckin' dream.
 

thebufenator

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VIA KT133a - KT400 were not bad.

I owned a few boards with those chipsets, had a great time. Abit, and Shuttle made a couple of good Athlon boards back then.

KX7-333R anyone?
 

OutOfPhase

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This is one of those "perspective is everything" moments - but I had really good luck with my SIS chipset systems. I will attribute this to luck, given the sentiment here!
 

Keljian

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AMD's 5x86 was pretty much a fast 486, but used a 486 motherboard. In fact no chip I'm aware of used a Pentium P54c or P55c socket with a 486-like architecture.

The Winchip and Winchip 2 were CISC chips with single, in order, instruction pipelines. This is very different from the rest of the P5 generation (K5, 6x86) which had multiple pipelines, register renaming and superscalar execution. Branch prediction came in with the Winchip2.

While you could argue that the inclusion of mmx and 3dnow! make it a 5th generation design, in my opinion it's definitely more akin to the 486 design.
 
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hlfbkd420

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I don't know, the Celery 300A was kind of fun for a bit.

Yup... Proud owner of a Dual Socket Abit board with two 300A's overclocked to hilt with peltier coolers back in the day. Thing was a beast.. Cheap too.
 
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Nenu

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I threw a bunch of old kit out a few months ago but removed the processors and I'm sure I've got at least one 300A.
The CPUs almost went as well but at the last moment I ripped them out of the mobos.
Dont blame me, I had orders to clear space!
 

enindee

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My dad once came home with a new desktop pc to replace the ancient K6-2 500mhz we had. It had a Sempron 3000+ in it... I hated that thing even more than the K6-2.
 

J3RK

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I threw a bunch of old kit out a few months ago but removed the processors and I'm sure I've got at least one 300A.
The CPUs almost went as well but at the last moment I ripped them out of the mobos.
Dont blame me, I had orders to clear space!

Have them dipped in gold, and embedded in some crystal. They can live on as executive paper-weights. :D
 

you2

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Life would be different if the 6800 had been used in the pc rather than the 8088 and I could never stand the 80186 or 80286 hacks.
 

dexvx

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SiS VIA ALi Promise & Win9x....I am really thankful that those days are gone.

Seems strange. SiS and Via were pretty reliable for the 386/486 in terms of motherboard. I mean, Intel didn't even make a 386 chipset, and their first 486 chipset trailed the 486 by over 2 years.

And up until Socket 939, Via was probably the best chipset for AMD CPU's (meh to nForce).
 

Keljian

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No Via was NEVER the best option for AMD cpus ... none of their K5/6 chips worked well on the via boards, and the athlon boards were plagued with issues (which software tried to fix)
 

cyclone3d

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The AMD K6 with 3DNow! was the worst processor I had to deal with. It had most blue screens of death and computer crashes I have ever seen. Constant integer divide by zero errors. I believed I figured that error out but by that time I had enough dealing with it and got rid of it after owning it for a month. I haven't touched AMD since then.

Sounds to me like you had one or more problems:
Faulty CPU
Faulty or incompatible RAM
Crappy/faulty/incompatible motherboard
Crappy/faulty PSU
Overheating CPU
 

J3RK

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Life would be different if the 6800 had been used in the pc rather than the 8088 and I could never stand the 80186 or 80286 hacks.

That's what Amigas were for until around the 386 DX-40 era or so. Then they started losing steam in comparison. (not that even at that point x86 was any better really, it was just too widely adopted at that point) 680x0 were nice enough. I think further iterations of the MIPS R3000+ processors could have been cool too if they had progressed further than they did. All that said, I had an Amiga and a 286 with VGA and a Soundblaster 1.0 sitting side by side, and having both was really nice at the time. (late '89 I should think)
 

Nenu

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That's what Amigas were for until around the 386 DX-40 era or so. Then they started losing steam in comparison. (not that even at that point x86 was any better really, it was just too widely adopted at that point) 680x0 were nice enough. I think further iterations of the MIPS R3000+ processors could have been cool too if they had progressed further than they did. All that said, I had an Amiga and a 286 with VGA and a Soundblaster 1.0 sitting side by side, and having both was really nice at the time. (late '89 I should think)
Similar, I had an A600 and a 286 PC + soundblaster (cant remember which) with something like a 40MB MFM hard drive running RLL for 50% more space heh.
The Amiga blew all over the PC for gaming.
Like you said, when 386s had been out a while they drew level for gaming and then took over for game coverage.

Quite a few years later a neighbour wanted a cheap gaming system and couldnt afford much because they were buying the house.
I talked them out of a console and got them a second hand A600 with a ton of games.
They were over the moon.
The 68K was very good in its day.
 
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J3RK

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Ah the MFM hard drive. I love the little chirping and whirring sounds those made. Funny actually, when I was playing Unreal on its birthday the other day, I had forgotten that they used that sound heavily in the opening prison ship. :D It was also used in Shogo if I remember correctly. I've also heard it all over cartoons like Dexter's Lab. Whir Whir Whir, Chirp Chirp, Whir Whir Whir, ChkaChka, Chirp Chirp..... :D
 

you2

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Is that what the victor 9000 had ? It had this funky floppy drive that had much higher capacity than the ibm at the time.

Ah the MFM hard drive. I love the little chirping and whirring sounds those made. Funny actually, when I was playing Unreal on its birthday the other day, I had forgotten that they used that sound heavily in the opening prison ship. :D It was also used in Shogo if I remember correctly. I've also heard it all over cartoons like Dexter's Lab. Whir Whir Whir, Chirp Chirp, Whir Whir Whir, ChkaChka, Chirp Chirp..... :D
 
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