6 ms·

Something has to be said about clock race too... Even the Sun workstation with 68020 Motorola CPU would only clock at 16 to 20 Mhz I think. Meanwhile the 386 ca

Something has to be said about clock race too... Even the Sun workstation with 68020 Motorola CPU would only clock at 16 to 20 Mhz I think. Meanwhile the 386 came out in 1985 (announced in 1984 according to Wikipedia) and could go to 40 Mhz. One answer on SO (with only six upvotes) says that Motorola couldn't keep up the clock race. When technology is advancing at an insane pace and you see a CPU line that is already not keeping up with the clock race, it probably doesn't make much sense to bet on that CPU line. I remember going from my beloved Commodore Amiga (68000) to a PC felt like going back in time but the PC's 386 would clock at 40 Mhz while the Amiga would clock a... 7 Mhz. So there's that.

dboreham 3y ago
Except Intel clock cycles weren't the same as Motorola clock cycles.
- nxobject 3y ago
  I'm sure the fact that 68k evolved over its lifetime from an incredibly elaborate interpretive microcoded system to something that supported pipelined out-of-order doesn't help, either.
TheOtherHobbes 3y ago
Raw clocks matter far less than architectural efficiency and instruction throughput. A 16MHz 386 was around 2MIPS, around the same as a 12MHz 68000. A 40MHz 68040 was around 40MIPS, a 66MHz 468DX2 was around 25MIPS. The 68040 also had significantly faster floating point performance. It's slightly insane that the 68000 (released 1979) was comparable in performance to a VAX 11/780 (released 1977) - for a tiny fraction of the cost.
- justapassenger 3y ago
  They’re less meaningful, but they’re number. And numbers are easy to compare, with ignoring all the context.
  - mistrial9 3y ago
    lots of marketing relies on superficial understanding by the viewer, partial attention and mistaking good looks for other qualities. In other words, yes, agree.. look at the results in the markets.
    - mistrial9 3y ago
      one part of this has a formal name! -- The "anchoring effect" names a tendency to be influenced by irrelevant numbers. Shown greater/lesser numbers, experimental subjects gave greater/lesser responses. https://en.wikipedia.org/wiki/Anchoring_(cognitive_bias) https://en.wikipedia.org/wiki/Anchoring_(cognitive_bias)
- segmondy 3y ago
  The public didn't know this. Regular John and Jane belive that higher Mhz means faster.
- qubex 3y ago
  MIPS, which at about that time was derided as “Meaningless Integer Performance Statistic” by those who moved in the supercomputing (now ‘HPC’) circles.
- cmrdporcupine 3y ago
  That said, 68000 interrupt responsiveness wasn't great at all when compared the 8-bit systems it was replacing. An Atari ST is positively insane in the # of cycles it took to respond to an interrupt vs e.g. the C64 which was designed by some of the same people. Wider bus, more registers, different design constraints. The 68000 was great for doing what you mention: bringing VAX-like tech to the masses. Looking back I don't think it was a great "home computer" processor, and not great for games and the like, either. In anyways, I'd say by the mid-90s the 68k architecture could not keep up with x86 because Motorola just stopped investing in it.
lgg 3y ago
It is a pretty easy mistake to make if you are used to how fast new processors come out now, but you comparing an i386 from 1991 to to a 68020 from the mid 80s. In 1985 when the 386 came out I believe the fastest speed you could get was 16MHz. They added higher speed variants for years afterwards. Intel made a 40MHz 386 in 1991 that was strictly aimed at embedded users who want more perf but were not ready to move to 486 based designs (386CX40), I doubt almost anyone used on in a PC. AMD made a Am386 at 40MHz which was a reverse engineered clone of the 386, but again that came out in the 90s (the big selling point was that you could reuse your existing 386 motherboards instead of replacing them like you needed to for a 486).
rasz 3y ago
40MHz 386 was is 1992. Amiga is another issue, Commodore was selling same 1985 design with no improvements all the way to 1992, and with only very minor ones past that.
- inglor_cz 3y ago
  "40MHz 386 was is 1992." It was also the lowest configuration on which Doom could run decently in full screen mode.
13of40 3y ago
The Amiga outsourced a lot of its work to custom peripheral chips, so doing something like a mass move of memory from one location to another, on a bit boundary, didn't rely on the CPU. Likewise, you could change the addresses of video bitplanes, which could give the illusion of graphics animation without doing huge memory moves. All of that accumulated to mean an Amiga had a better human interface than a PC, at least in that era, even if the PC could do more math.
- cmrdporcupine 3y ago
  Yeah but it's an architecture that couldn't make it past the late 80s. For one because it couldn't keep pace with Moore's law and economies of scale. Custom chips are expensive and the talent to design them hard to source. But most importantly the bus multiplexing on systems like that -- sharing video memory between CPU and dedicated coprocessor -- makes no sense in the 90s and beyond when memory became many multiples slower than the CPU. The whole assumption of the Jay Miner design is that the coprocessor could do things faster than the CPU. ... but then CPUs just became way faster than main memory, and those fancy coprocessors would have been sitting there waiting on the bus just like anything else. When GPUs came on the scene, they took a very different path. They have their own memory, and do very specialist things, and for a long time were very limited in the kind of bandwidth they had back to the CPU, too. Anyways, Amiga had a nice system for 1986. By the 90s it was pointless and mass produced ISA video cards outpaced it, and they did so with a design entirely different. Amiga and systems like it are not "paths not taken", they're design dead-ends.
  - icedchai 3y ago
    With later systems, the coprocessors (blitter, at least) were often slower than the CPU. I remember having an A3000 and installing "CpuBlit" (see http://aminet.net/package/util/boot/CpuBlit http://aminet.net/package/util/boot/CpuBlit ) Text scrolling speeds were vastly improved!
    - cmrdporcupine 3y ago
      Exactly; there was a similar situation with Atari corp. Initial ST shipped without the planned but not finished yet "blitter" chip. With the STe they rolled that out, but a couple years later and it never got good market penetration. But by the time they got to the late 80s with the TT030 and the Falcon 030 it become pointless because main CPU was in most cases faster than hardware blitting. That's the problem with custom chips. An approach that was invaluable in the 70s and 80s for the 8-bit machines, but became a handicap by the 90s.
deleted 3y ago
[deleted]

dboreham 3y ago

Except Intel clock cycles weren't the same as Motorola clock cycles.

nxobject 3y ago
I'm sure the fact that 68k evolved over its lifetime from an incredibly elaborate interpretive microcoded system to something that supported pipelined out-of-order doesn't help, either.

TheOtherHobbes 3y ago

Raw clocks matter far less than architectural efficiency and instruction throughput. A 16MHz 386 was around 2MIPS, around the same as a 12MHz 68000. A 40MHz 68040 was around 40MIPS, a 66MHz 468DX2 was around 25MIPS. The 68040 also had significantly faster floating point performance. It's slightly insane that the 68000 (released 1979) was comparable in performance to a VAX 11/780 (released 1977) - for a tiny fraction of the cost.

justapassenger 3y ago
They’re less meaningful, but they’re number. And numbers are easy to compare, with ignoring all the context.
- mistrial9 3y ago
  lots of marketing relies on superficial understanding by the viewer, partial attention and mistaking good looks for other qualities. In other words, yes, agree.. look at the results in the markets.
  - mistrial9 3y ago
    one part of this has a formal name! -- The "anchoring effect" names a tendency to be influenced by irrelevant numbers. Shown greater/lesser numbers, experimental subjects gave greater/lesser responses. https://en.wikipedia.org/wiki/Anchoring_(cognitive_bias) https://en.wikipedia.org/wiki/Anchoring_(cognitive_bias)
segmondy 3y ago
The public didn't know this. Regular John and Jane belive that higher Mhz means faster.
qubex 3y ago
MIPS, which at about that time was derided as “Meaningless Integer Performance Statistic” by those who moved in the supercomputing (now ‘HPC’) circles.
cmrdporcupine 3y ago
That said, 68000 interrupt responsiveness wasn't great at all when compared the 8-bit systems it was replacing. An Atari ST is positively insane in the # of cycles it took to respond to an interrupt vs e.g. the C64 which was designed by some of the same people. Wider bus, more registers, different design constraints. The 68000 was great for doing what you mention: bringing VAX-like tech to the masses. Looking back I don't think it was a great "home computer" processor, and not great for games and the like, either. In anyways, I'd say by the mid-90s the 68k architecture could not keep up with x86 because Motorola just stopped investing in it.

lgg 3y ago

It is a pretty easy mistake to make if you are used to how fast new processors come out now, but you comparing an i386 from 1991 to to a 68020 from the mid 80s. In 1985 when the 386 came out I believe the fastest speed you could get was 16MHz. They added higher speed variants for years afterwards. Intel made a 40MHz 386 in 1991 that was strictly aimed at embedded users who want more perf but were not ready to move to 486 based designs (386CX40), I doubt almost anyone used on in a PC. AMD made a Am386 at 40MHz which was a reverse engineered clone of the 386, but again that came out in the 90s (the big selling point was that you could reuse your existing 386 motherboards instead of replacing them like you needed to for a 486).

rasz 3y ago

40MHz 386 was is 1992. Amiga is another issue, Commodore was selling same 1985 design with no improvements all the way to 1992, and with only very minor ones past that.

inglor_cz 3y ago
"40MHz 386 was is 1992." It was also the lowest configuration on which Doom could run decently in full screen mode.

13of40 3y ago

The Amiga outsourced a lot of its work to custom peripheral chips, so doing something like a mass move of memory from one location to another, on a bit boundary, didn't rely on the CPU. Likewise, you could change the addresses of video bitplanes, which could give the illusion of graphics animation without doing huge memory moves. All of that accumulated to mean an Amiga had a better human interface than a PC, at least in that era, even if the PC could do more math.

cmrdporcupine 3y ago
Yeah but it's an architecture that couldn't make it past the late 80s. For one because it couldn't keep pace with Moore's law and economies of scale. Custom chips are expensive and the talent to design them hard to source. But most importantly the bus multiplexing on systems like that -- sharing video memory between CPU and dedicated coprocessor -- makes no sense in the 90s and beyond when memory became many multiples slower than the CPU. The whole assumption of the Jay Miner design is that the coprocessor could do things faster than the CPU. ... but then CPUs just became way faster than main memory, and those fancy coprocessors would have been sitting there waiting on the bus just like anything else. When GPUs came on the scene, they took a very different path. They have their own memory, and do very specialist things, and for a long time were very limited in the kind of bandwidth they had back to the CPU, too. Anyways, Amiga had a nice system for 1986. By the 90s it was pointless and mass produced ISA video cards outpaced it, and they did so with a design entirely different. Amiga and systems like it are not "paths not taken", they're design dead-ends.
- icedchai 3y ago
  With later systems, the coprocessors (blitter, at least) were often slower than the CPU. I remember having an A3000 and installing "CpuBlit" (see http://aminet.net/package/util/boot/CpuBlit http://aminet.net/package/util/boot/CpuBlit ) Text scrolling speeds were vastly improved!
  - cmrdporcupine 3y ago
    Exactly; there was a similar situation with Atari corp. Initial ST shipped without the planned but not finished yet "blitter" chip. With the STe they rolled that out, but a couple years later and it never got good market penetration. But by the time they got to the late 80s with the TT030 and the Falcon 030 it become pointless because main CPU was in most cases faster than hardware blitting. That's the problem with custom chips. An approach that was invaluable in the 70s and 80s for the 8-bit machines, but became a handicap by the 90s.

deleted 3y ago

[deleted]