3 ms·

> ram scavanged from an old 486 (edo ram) EDO was from the 2nd generation of Pentium. It was not a 486 thing and I never even heard of any 486 that could use E

by lproven 10mo ago

> ram scavanged from an old 486 (edo ram) EDO was from the 2nd generation of Pentium. It was not a 486 thing and I never even heard of any 486 that could use EDO. The 1st gen Pentium chips were 5V parts running at 60 MHz or 66 MHz. The 2nd gen were 3.3V and ran at 75, 90 or 100 MHz. The critical development for EDO was Intel's Triton chipset (the 82430FX) which added EDO support for about 15% more memory bandwidth. I ran the testing labs for PC Pro magazine at that time and Tulip Computers of the Netherlands sent in a Pentium with an SIS chipset that could detect EDO but not use EDO's timings, so it was no quicker. I wrote about it. (This was circa 1995. 486 introduced 1989. P5 (5V) 1993. P54C (3.3V) 1994.) Tulip threatened to sue. The board and some lawyers flew to London. I demonstrated that their PC could detect EDO and showed a message that EDO was fitted which did not appear if FP-mode DRAM was. I then showed that a machine with a 430FX chipset was circa 15% quicker with EDO than FP RAM, and the Tulip was the same speed. The threat of litigation was withdrawn and Tulip used our phone to make an international call to Taiwan there and then to shout at SIS. I worked extensively with this stuff. No 486s with EDO to the best of my expert knowledge.

rasz 10mo ago
A lot of SIS chipsets claimed EDO support, but with such bad timings there was no gain or even loss https://www.vogons.org/viewtopic.php?p=1378307#p1378307 https://www.vogons.org/viewtopic.php?p=1378307#p1378307 "I see no performance difference between EDO and FPM" Legit 486 EDO chipset is UMC 8881E/F https://www.vogons.org/viewtopic.php?t=93147 https://www.vogons.org/viewtopic.php?t=93147 "486 board with UMC 8881E/8886B: The winner is: EDO without L2 (if your only other option is L2 at 3-2-2-2)" TLDR: standard on any 486 motherboard L2 cache masks any EDO mode gains, even when EDO runs with fastest supported 3-1-1-1 timings.
- lproven 10mo ago
  > with such bad timings there was no gain or even loss Yes, that is what I discovered, experimentally verified, and published -- in 1995 or so, some 24 years before that post. > Legit 486 EDO chipset is UMC 8881E/F I am not sure what you're saying here. This seems like a very messy mix of conclusions... * At least one 486 chipset can use EDO -- sure, no problem, I can believe that. But was it designed to use EDO timings? I doubt that: 486 family chips were fading legacy tech when EDO was first invented. * Quake benchmarks: Quake was hand-coded to interleave FPU and integer ops in a way that used an inherent property of the Pentium hardware design. I went into this in some depth in 2016 here: https://liam-on-linux.livejournal.com/49259.html https://liam-on-linux.livejournal.com/49259.html The int/FP interleaving didn't work on any other CPU. Not on 486, 5x86, 6x86, anything. So small performance differences on a 486-class chip do not really tell us anything meaningful here, IMHO.
  - rasz 10mo ago
    >But was it designed to use EDO timings? Yes, this chipset can do EDO 3-1-1-1. Of course problem is Cache can also run at 3-2-2-2 or 3-1-1-1 and board doesnt have buffers between ram and rest of the system thus in EDO mode you need one more cycle to close the page after every burst to unlock data bus. EDO = extended Output = ram keeps outputting last accessed data. Early Intel Pentium chipsets included additional chips performing that buffering between system and ram (for example 82438VX). Still even 430VX slowed down to standard FPM 7-3-3-3 timings with EDO and Async cache, only burst pipelined cache allowed 6-2-2-2. The big Pentium era performance jump seemed to come from pipelined cache significantly unlocking ram subsystem potential https://dependency-injection.com/early-pentium-chipsets/ https://dependency-injection.com/early-pentium-chipsets/ Just the EDO vs FPM difference was small around 1-3% depending on the cache situation.
    - lproven 10mo ago
      > Yes, this chipset can do EDO 3-1-1-1. All right, I will take your word for it. When did it come out, though? I think EDO RAM didn't start to appear until the early/mid 1990s -- 1993/1994 or so at the earliest. This was very late in the lifespan of 486 chips (and enhanced ones like 586s) and so this would have been a small performance tweak for very low-end budget hardware, surely? > Early Intel Pentium chipsets included additional chips performing that buffering between system and ram (for example 82438VX). Hang on. The 430VX was not an early Pentium chipset. It was a late one. It launched in 1996: https://theretroweb.com/chipsets/277 https://theretroweb.com/chipsets/277 After the "Triton", the 430FX: https://dosdays.co.uk/topics/intel_chipsets.php https://dosdays.co.uk/topics/intel_chipsets.php The dominant early Intel chipset for Pentium hardware was the 430NX "Neptune". I had a Neptune-based PC at work, originally with a Pentium 66 in it, later replaced with a PODP, the Pentium Overdrive, with a clock-doubled 3.3V P54 chip in a socket adaptor. Neptune was nothing special and had no performance boosts to speak of. The only interesting thing is that as it didn't have built-in EIDE, it was often on a PCI card. I removed it from my all-SCSI machine for a "purer" setup with nothing using the EIDE I/O ports and DMA channels. Triton (430FX) brought in EDO support, and was as I said about 15% faster with all other factors being equal: same CPU, same cache, same drives, same graphics, etc. This is the time period when I developed the 32-bit version of PC Pro magazine's 16-bit Windows benchmark. I was very familiar with PC performance and components back then. The DosDays website is confusing because it lists the chipsets in this order: NX "Neptune" FX "Triton" HX "Triton II" TX "Triton IV" VX "Triton III" ... when its own dates show that the TX came later, and it really went: NX FX HX/VX more or less simultaneously and both termed Triton II TX <- I don't think I ever saw this I strongly disagree with your comment about cache. Cache/no cache was huge. Write-back vs write-through was huge. Pipelined burst cache helped a lot but any L2 cache was good. No, the type of cache wasn't a big difference: having it at all was what mattered. Cheap cloners had no L2 cache and modified the startup messages to say "writeback cache" meaning that only L1 cache was present. Aside from bargain-basement skipware, most Pentium boxes that were any good had Intel chipsets and L2 cache. Usually only enough for caching the first 64MB.

by lproven 10mo ago

rasz 10mo ago

A lot of SIS chipsets claimed EDO support, but with such bad timings there was no gain or even loss https://www.vogons.org/viewtopic.php?p=1378307#p1378307 https://www.vogons.org/viewtopic.php?p=1378307#p1378307 "I see no performance difference between EDO and FPM" Legit 486 EDO chipset is UMC 8881E/F https://www.vogons.org/viewtopic.php?t=93147 https://www.vogons.org/viewtopic.php?t=93147 "486 board with UMC 8881E/8886B: The winner is: EDO without L2 (if your only other option is L2 at 3-2-2-2)" TLDR: standard on any 486 motherboard L2 cache masks any EDO mode gains, even when EDO runs with fastest supported 3-1-1-1 timings.

lproven 10mo ago
> with such bad timings there was no gain or even loss Yes, that is what I discovered, experimentally verified, and published -- in 1995 or so, some 24 years before that post. > Legit 486 EDO chipset is UMC 8881E/F I am not sure what you're saying here. This seems like a very messy mix of conclusions... * At least one 486 chipset can use EDO -- sure, no problem, I can believe that. But was it designed to use EDO timings? I doubt that: 486 family chips were fading legacy tech when EDO was first invented. * Quake benchmarks: Quake was hand-coded to interleave FPU and integer ops in a way that used an inherent property of the Pentium hardware design. I went into this in some depth in 2016 here: https://liam-on-linux.livejournal.com/49259.html https://liam-on-linux.livejournal.com/49259.html The int/FP interleaving didn't work on any other CPU. Not on 486, 5x86, 6x86, anything. So small performance differences on a 486-class chip do not really tell us anything meaningful here, IMHO.
- rasz 10mo ago
  >But was it designed to use EDO timings? Yes, this chipset can do EDO 3-1-1-1. Of course problem is Cache can also run at 3-2-2-2 or 3-1-1-1 and board doesnt have buffers between ram and rest of the system thus in EDO mode you need one more cycle to close the page after every burst to unlock data bus. EDO = extended Output = ram keeps outputting last accessed data. Early Intel Pentium chipsets included additional chips performing that buffering between system and ram (for example 82438VX). Still even 430VX slowed down to standard FPM 7-3-3-3 timings with EDO and Async cache, only burst pipelined cache allowed 6-2-2-2. The big Pentium era performance jump seemed to come from pipelined cache significantly unlocking ram subsystem potential https://dependency-injection.com/early-pentium-chipsets/ https://dependency-injection.com/early-pentium-chipsets/ Just the EDO vs FPM difference was small around 1-3% depending on the cache situation.
  - lproven 10mo ago
    > Yes, this chipset can do EDO 3-1-1-1. All right, I will take your word for it. When did it come out, though? I think EDO RAM didn't start to appear until the early/mid 1990s -- 1993/1994 or so at the earliest. This was very late in the lifespan of 486 chips (and enhanced ones like 586s) and so this would have been a small performance tweak for very low-end budget hardware, surely? > Early Intel Pentium chipsets included additional chips performing that buffering between system and ram (for example 82438VX). Hang on. The 430VX was not an early Pentium chipset. It was a late one. It launched in 1996: https://theretroweb.com/chipsets/277 https://theretroweb.com/chipsets/277 After the "Triton", the 430FX: https://dosdays.co.uk/topics/intel_chipsets.php https://dosdays.co.uk/topics/intel_chipsets.php The dominant early Intel chipset for Pentium hardware was the 430NX "Neptune". I had a Neptune-based PC at work, originally with a Pentium 66 in it, later replaced with a PODP, the Pentium Overdrive, with a clock-doubled 3.3V P54 chip in a socket adaptor. Neptune was nothing special and had no performance boosts to speak of. The only interesting thing is that as it didn't have built-in EIDE, it was often on a PCI card. I removed it from my all-SCSI machine for a "purer" setup with nothing using the EIDE I/O ports and DMA channels. Triton (430FX) brought in EDO support, and was as I said about 15% faster with all other factors being equal: same CPU, same cache, same drives, same graphics, etc. This is the time period when I developed the 32-bit version of PC Pro magazine's 16-bit Windows benchmark. I was very familiar with PC performance and components back then. The DosDays website is confusing because it lists the chipsets in this order: NX "Neptune" FX "Triton" HX "Triton II" TX "Triton IV" VX "Triton III" ... when its own dates show that the TX came later, and it really went: NX FX HX/VX more or less simultaneously and both termed Triton II TX <- I don't think I ever saw this I strongly disagree with your comment about cache. Cache/no cache was huge. Write-back vs write-through was huge. Pipelined burst cache helped a lot but any L2 cache was good. No, the type of cache wasn't a big difference: having it at all was what mattered. Cheap cloners had no L2 cache and modified the startup messages to say "writeback cache" meaning that only L1 cache was present. Aside from bargain-basement skipware, most Pentium boxes that were any good had Intel chipsets and L2 cache. Usually only enough for caching the first 64MB.