Vintage computer speeds

[IBMMuseum]

Vintage computer speeds

Just to chime in, I had two 386/16 machines. One was a laptop (which I still have). The other was a Packard Bell desktop that ran my BBS for many years. )

Both were probably the 386SX, which was very common for a 386 laptop or budget system (I haven't see too many Packard Bell 386DXs). What is really cool is if you can get a BIOS CPUID out of them. Typically it has to be something like a Phoenix (which may cover the Packard Bell unit) or IBM BIOS.

I don't remember ever seeing a 386/12. I do remember my family's 286 did 10/12 (turbo). The most popular 386 speeds that I recall were 16, 25, 33, and 40 (I had a dx2/40).

The 386-12 (before even the "DX" designation) was the very start of the cycle, when they couldn't get the CPUs marked that way to run any faster. Many initial 386 chips ended up being replaced for a few different bugs (32-bit multiply, "Errata 21" 386, etc.). If you have one with "DX" in the part number then it doesn't have the early bugs (the 386DX was very past its prime when Intel finally fixed most of the known bugs in the 'F' step).
The first 386 (what later became the 'DX' chips) stepping was "A". Intel had at least one machine instruction code that was pulled off the later releases. Interesting as well is seeing an Intel 386DX core in IBM's standard packaging at that time of silver chips (I have the only Intel 386DX 'C' step I have ever heard of in that form).
286 motherboards even went up to 20MHz towards the end of the cycle. For a number of years it's been easy enough to find 286-16 motherboards. And 12Mhz 286s were pretty common (a 16Mb RAM barrier wasn't even thought about, because I remember it was damn hard & expensive to get that high with DIP chips).
386 CPU (both DX & SX flavors) speeds were 16, 20, 25, 33, & 40MHz. The last wasn't an Intel speed, but you could find it with AMD & others. There was also some 486 variants made by Cyrix, TI, & IBM that worked with the same pinouts. Usually these wouldn't have been labelled as a "dx2", but there was all kinds of confusing designations.

 

[carlsson]

I have an AMD 486SX/2-66. It was retrofitted (?!) into a Compaq Prolinea 25/NET, which based on its model number should've had a 486SX-25 in the original configuration. I never understood what NET means, because there definitely was no integrated networking, not even a modem IIRC. I upgraded with an Intel 486DX/2-66, but I'm unsure if it made any improvement over the AMD chip.

 

[Terry Yager]

Not bad for an emulation.

Kent

Hardware emulation usually is faster than software. I had to go to a low-end '486 before I could get any decent speed for software CP/M emulators comparable to the speed of a 'Blue Thunder' Z80 board running in a 4.77MHz PC.

--T

 

[Terry Yager]

Ok, I remembered recently reading a long time ago that someone claimed that a 68000 and a 80386DX - at the same clock speed (say 16MHz) performed identically. That got me thinking, has anyone got any speed comparisons between different CPUs? Say 6502 Vs Z80, AMD 386DX Vs Intel 80386 Vs 68000, or 6502 Vs 8088?

I know that a straight speed comparison between different platforms isn't usually valid, due to many things - Operating system (where applicable), supporting hardware, differences in the CPUs themselves, etc., but even a rough idea of where they all fit in against each other would be interesting, wouldn't it?

Perhaps if we could find out the Instructions Per Clock for the majority of instructions for each CPU, then take into account what clock speeds they ran at, and work it out that way?

Any ideas, suggestions, opinions?

I did play around a little, a couple of years back, comparing 8085 vs Z80 vs 6301-based machines, running a couple of BASIC programs. The results are posted here:

http://www.vintage-computer.com/vcforum/showthread.php?t=854&page=2&highlight=benchmark

--T

 

[IBMMuseum]

Vintage computer speeds

I have an AMD 486SX/2-66. It was retrofitted (?!) into a Compaq Prolinea 25/NET, which based on its model number should've had a 486SX-25 in the original configuration. ...I upgraded with an Intel 486DX/2-66, but I'm unsure if it made any improvement over the AMD chip.

You added a math coprocessor. Intel only made 486SX2-50s, but AMD made both a 50 & 66MHz version. Unless you changed jumper setting for speed it might have just been running the 486SX2/486DX2 at 50MHz internally.

 

[carlsson]

Yes, I was careful to get the jumper settings as good as possible, and verify with the Compaq configuration software that it was detected correctly.

 

[rmay635703]

The rarest CPU I can think of in the 386 pinout is the old DX3 IBM/Cyrix blue lightning chips that did indeed go as high as 100mhz, very very rare though.

There were many variations of 386 chips above 40mhz that had bastardized names made by IBM/Cyrix in the early days many of the blue lightning chips were thus. I had an old IBM Blue lighting 486 SLC-2 66mhz which was just a fancy 386sx clock multiplied, too bad I gave it away in my ignorance.

 

[IBMMuseum]

The rarest CPU I can think of in the 386 pinout is the old DX3 IBM/Cyrix blue lightning chips that did indeed go as high as 100mhz, very very rare though.

There were many variations of 386 chips above 40mhz that had bastardized names made by IBM/Cyrix in the early days many of the blue lightning chips were thus. I had an old IBM Blue lighting 486 SLC-2 66mhz which was just a fancy 386sx clock multiplied, too bad I gave it away in my ignorance.

At lower speeds variations of those chips were more common. There was a CPU IBM made in the 386DX PQFP style (AMD did some 386DX-40s this way, but Intel pretty much did PGA with it's 386DXs) that could be wired up as full 32-bit (like a 386DX) or 16-bit/24 address lines (like a 386SX). On the 16-bit side it was called a 486SLC3 & commonly at 75MHz internally (but could only address 16Mb of RAM on the system).

Much more than a glorified 386SX, IBM's productions were very novel for their time (and deployed on several PS/2s & other IBM systems). IBM generally had free license to improve certain Intel CPU codemasks at one point (and why some of the joint work with Cyrix existed later). The models are:

386SLC (common in 16 & 20MHz): Even though it has "386" in the name, it can run all Intel 486SX instructions. Not clock multiplied internally. It has a 8Kb L1 cache to further improve performance over the 386SX, which it in the same package. 16-bit data, 24-bit address bus (like the 286 and 386SX, for 16Mb maximum system RAM).

486SLC2 (typically in packages able to go up to 50Mhz & 66MHz internally): Runs all Intel 486SX instructions. Clock doubled internally. 16Kb L1 cache. 16-bit data, 24-bit address bus, in a 386SX style package.

486SLC3 (in 16-bit mode quite commonly they could be 75MHz internally): Runs all Intel 486SX instructions. Clock tripled internally. 16Kb L1 cache. In a 386DX PQFP style, but in 16-bit mode it is a 16-bit data bus, 24-bit address bus CPU.

Anybody want to see pictures? Or know of the systems they are commonly in? I have dozens literally within my reach.

 

[Flack]

After a week long grueling battle, I just got my old 486 dx4/100 back online. I had to deal with a stand off -- I needed to reload Windows 98 on it but the floppy drive wasn't working, so without that I couldn't boot off a boot disk and reload Windows.

 

[rmay635703]

I had a baby AT ISA/VLB motherboard with the IBM Blue Lightning logo 486SLC2-66mhz didn't look into it much at the time but it was NOT for a proprietary system, just a simple upgrade board for use in any AT case, had a neat blue logo silkscreened on the board. Too bad I got rid of it...

 

[Mike Chambers]

After a week long grueling battle, I just got my old 486 dx4/100 back online. I had to deal with a stand off -- I needed to reload Windows 98 on it but the floppy drive wasn't working, so without that I couldn't boot off a boot disk and reload Windows.

hehe, i just set my old 486 dx4/100 up too actually. it's an IBM machine with built-in video card. i don't remember the model number offhand. i would greatly reccommend you installing NT4 workstation on it rather than 98.

interesting story behind how i got that thing. back in march i went downtown with a couple friends for a st. patrick's day party at some guys house. a few houses up the street from him, somebody had two computers and a dot matrix printer out by the curb for the garbage pick up.

since seeing old systems get trashed like that makes baby Jesus cry, i thought i'd give that stuff a loving home. turns out they were both 486's. i took the IBM machine and one of my friend's took the other one, which was actually some custom built machine. (also, my other friend grabbed the epson dot matrix printer and smashed it on the street. i almost killed him!)

my friend turned his 486 into a debian box running in console mode to act as some sort of server (i forget what he's actually serving with it)

in the end, i had gotten the better of the two. his was an sx 33 lol. :D

but yeah, both of our machines run flawlessly and mine even had 64 MB of RAM installed in it. scandisk reports no errors on it's 256 MB IBM hard disk after a surface scan. (it's an H3256-A3 model drive as i recall)

i need to go dumpster diving more often