Forum Rules and Etiquette

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386 performance ceiling?

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    386 performance ceiling?

    OK now, I've thrown everything I could to my 386 PC. It is now like:

    CPU: 80386DX-40 (AMD) / 80387DX (IIT3C87-40)
    Mainboard: 4386-VC-HD ( )
    Cache: 128K L2 cache
    RAM: 32 MB RAM 60ns non-parity ECC
    Video card: Tseng Labs ET4000 W32, or S3 928

    As you can see, everything is the most advanced I can fit in, apart from the cache, where I tried to add another 128K (from a 486 board) but couldn't get a stable system. The PC still gets its ass handed to it performance wise, compared to a Pentium 133MHz, S3 Trio 64V+ card, 70ns RAM that I have. I was hoping that all these upgrades would somehow bridge the gap, but I guess I was wrong, as the performance difference is still so big that it is obvious without even the need to run a benchmark suit.

    May just be wishful thinking. I'm not sure what you were doing to hope it'd compete with a Pentium. Honestly even 486 to Pentium was a nice performance increase. There are lots of internal tweaks with the opcode timing, predictive commands (at least in the K6-2 world) and other tricks that came out it'd be kinda hard to keep up with the new beasts in town.

    You could certainly benchmark it against your other changes though and see what makes the biggest improvements. I'm sure your 386 is pretty damn sweet compared to others though.
    Looking to acquire: IBM 5100, Altair 8800


      I'm not sure what you expected, comparing a 386 to a Pentium. My architecture is a bit hazy, but I'm pretty sure the 486 and moreso the Pentium benefit greatly from pipe-lining, which is going to give any chip a large advantage.


        In other news, no matter how many upgrades I add to my Pentium 3, it is just smoked by my Core 2 Duo...

        Yeah, 386-to-Pentium is such a huge jump, you're not going to make up ground. The only way you could POSSIBLY get a 386 to be faster would be to purposefully hobble the Pentium. (Pentium 60, slow ISA video card, etc.)

        Not to mention, you're using a video chip on your 386 that was designed for a 32-bit local bus (VESA, EISA, PCI,) it might even have its performance HINDERED by being used on an ISA card. Might be better off to get a fast designed-for-ISA chip.
        Apple ][+ through Retina MacBook Pro, 5150 PC through Core i7 8870/GeForce GTX 1080Ti and quad Itanium 9150M, and many in between.
        Newton, Palm 1000, Palm V, N-Gage, Tapwave Zodiac, iPhone, iPhone X.
        Intellivision, Game Boy through 3DS, Wii, XBone


          Yeah, there seem to be many speed critical differences. Integrated L1 cache, integrated FPU, higher instructions per cycle and the ISA bottleneck as well (although I'm not sure how much of a bottleneck ISA is, as I might be CPU limited). I got rather used to modern CPU development rythms (only 10-30% faster every next gen) and forgot that those times, 2 generations can have an entire 10x performance gap. Well, anyway, this 386 will do fine for my vintage collection as it now is. But maybe I'll need something better for an ultimate DOS/Windows 3.11 platform


            Well, to be fair, your motherboard is an ISA-only model, so bandwidth to peripherals is rather limited. Also remember that the 80386 was a very ambitious chip for the time, being Intel's first 32-bit x86 chip.

            Appreciate it for what it is.
            Reach me: vcfblackhole _at_ protonmail dot com.


              In my own testing I've found that a 386DX40, with 256KB cache and ET4000AX is about equivalent to a 25MHz 486 with equal cache and a Trident ISA video card.
              386 pulls ahead slightly in some games, the 486 is better in others.
              The 486 tends to be better in benchmarks though, but both machines feel pretty close in real world usage.

              If I put the ET4000 in the 486 I find its generally the better machine for gaming.

              I also tested an Intel 486DX4-100 against a socket 4 Pentium 60 with the same PCI S3 video card and, similar to the results above, I found that these two systems were fairly close as well. (obviously in FPU intensive stuff like Quake the pentium is significantly faster). Even in a Doom timedemo the 486 was slightly faster than the Pentium.

              So to extrapolate these very unscientific results, you'd need a 320MHz 386DX to even think about holding a candle to a 133MHz Pentium.
              The 386's lack of PCI will hinder it even more in disk and video intensive tasks (if you can find one of the seemingly rare 386 boards with VLB then this might bridge the gap a little bit, but not totally).

              In fact, have a look at this chart:

              You can see that in the benchmarks used, the Pentium 133 is about 10 times faster than the 386DX40. Admittedly they are synthetic CPU benchmarks but they give you an idea of what's going on.

              so, yeah, I think you might have been dreaming if you expected your 386 to put up a fight against a Pentium :P


                But remember, at one time, the 80386 was at the heart of a supercomputer.

                Reach me: vcfblackhole _at_ protonmail dot com.


                  The 386-40 was 1991 if memory serves me, and the Pentium 133 came around mid 1995. Its like comparing a late Pentium 4 to an i7. I LOVE my little 386. It works great for pre-pentium dos games. And if i want to run something newer I have a Pentium pro system. (not to mention a 486 build in progress) I have a computer for every major generation of processors. While its not an elegant solution, I do love collecting and assembling the computers, almost more so than actually using them!
                  It is a mistake to think you can solve any major problems just with potatoes.


                    As stated a 386/40 is about the same as a 486 DX/25 (mostly because of the slow 25mhz bus on the 486 vs 40 for the 386). It took an overclocked 486/133 (to 166) to get into speed of the first Pentium chips, or a Cyrix 5x120 or so which was a Pentium era chip stuffed into a 486 socket.
                    What I collect: 68K/Early PPC Mac, DOS/Win 3.1 era machines, Amiga/ST, C64/128
                    Nubus/ISA/VLB/MCA/EISA cards of all types
                    Boxed apps and games for the above systems
                    Analog video capture cards/software and complete systems


                      What about swaping the 386 for a 486dlc? Should nearly double performance.

                      My 386 rig just broke - need to find and repair the trace for the keyboard
                      386 vlb motherboard with 256k 15ns cache
                      Ti486 dlc (8kb l1 cache) clock doubled to 80mhz
                      Cyrix 3/487 mat copro
                      32mb 60ns ram
                      Vlb caching ide controller
                      Vlb 4mb 64bit vram

                      The machine runs win95 really well!


                        By cheating I was able to get my 386 almost to the level of a DX4-100 (minus FPU). It involved using IBM DLC3-100 chip with 16kb internal cache. It is technically a 386 chip on steroids. Of course you'll still need a 386 board with VLB slots if you want decent graphics performance.
                        "Will the Highways on the internets become more few?"

                        V'Ger XT


                          You can speed up the CPU by using a 486 class upgrade but that only works well for small programs that are CPU intensive. Once you start hitting the ISA bus for video, sound, HD data, massive RAM swapping, etc the whole system will show its age.
                          What I collect: 68K/Early PPC Mac, DOS/Win 3.1 era machines, Amiga/ST, C64/128
                          Nubus/ISA/VLB/MCA/EISA cards of all types
                          Boxed apps and games for the above systems
                          Analog video capture cards/software and complete systems


                            I pulled some 3d benchmarks with the DOS 3dbench. The results seemed pretty sensitive on the cache memory timings, so I might try to find a way to stabilize 256K cache in turbo mode:

                            ET4000W32/no cache: 8,4
                            ET4000W32/128K normal timing cache: 13
                            ET4000W32/128K fast timing cache: 14,2
                            ET4000W32/128K turbo timing cache (memtest86 fails): 14,4
                            ET4000W32/128K fast timing cache/FPU removed: 14,2
                            MXIC(old cheap vid card)/128K fast timing cache: 13,5

                            Comparing to others results here: ,the performance is OK, but could be better. VLB 386 systems don't have a significant performance increase, according to these numbers.


                              VLB 386 don't benefit from VLB with a regular 386 chip. But I noticed a pretty huge performance increase with the IBM DLC chip.
                              "Will the Highways on the internets become more few?"

                              V'Ger XT