rmay635703 wrote on 2021-07-05, 20:50:

Disruptor wrote on 2021-07-05, 14:27:

A 386/40 should have some cache.
Regardless whether DX or SX.

With cache an sx40 would give an early ISA only 386dx-33 a run for it’s money

Heck IBMs 386SLC seemed to run circles around identically clocked 386DXs but it may have also coincided with the IBM having local bus IDE and VGA VRS ISA all around on the DX.

I have one with cache and no, it doesn't really. A DX25 or thereabouts is my experience.

Caluser2000 wrote on 2021-07-05, 21:14:

In processing 16-bit instructions they wouldn't even come because it they do twice the processing compare to just one by 386DXs at the same clock speed. It'll be around the equivilent of a Harris 286/2o in that regard. That is one reason my first x86 system was a 286/16 instead of a 386SX16. I had done my research being to computers in general..😉 Folk go on about 32-bit instructions and Windows 3.x 386enhansed mode. The reality is Win3.1 is quicker in Standard mode.

So if anyone on vogons is a 286 basher and a 368SX fanboi at the same clock speed go and do some research before posting inaccurate information...😉 A 286 will steamroller a 386SX of the same clock speed processing 16-bit instructions.

Let's talk when you find a 40MHz 286.

appiah4 wrote on 2021-07-05, 22:16:

I have one with cache and no, it doesn't really. A DX25 or thereabouts is my experience. […]
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rmay635703 wrote on 2021-07-05, 20:50:

Disruptor wrote on 2021-07-05, 14:27:

A 386/40 should have some cache.
Regardless whether DX or SX.

With cache an sx40 would give an early ISA only 386dx-33 a run for it’s money

Heck IBMs 386SLC seemed to run circles around identically clocked 386DXs but it may have also coincided with the IBM having local bus IDE and VGA VRS ISA all around on the DX.

I have one with cache and no, it doesn't really. A DX25 or thereabouts is my experience.

Caluser2000 wrote on 2021-07-05, 21:14:

In processing 16-bit instructions they wouldn't even come because it they do twice the processing compare to just one by 386DXs at the same clock speed. It'll be around the equivilent of a Harris 286/2o in that regard. That is one reason my first x86 system was a 286/16 instead of a 386SX16. I had done my research being to computers in general..😉 Folk go on about 32-bit instructions and Windows 3.x 386enhansed mode. The reality is Win3.1 is quicker in Standard mode.

So if anyone on vogons is a 286 basher and a 368SX fanboi at the same clock speed go and do some research before posting inaccurate information...😉 A 286 will steamroller a 386SX of the same clock speed processing 16-bit instructions.

Let's talk when you find a 40MHz 286.

Harris 286/20 or 25 don't you mean?

You see speed isn't the be all to and all. How that cpu processes code is more crucial...😉

Disruptor wrote on 2021-07-05, 14:27:

A 386/40 should have some cache.
Regardless whether DX or SX.

Depends..
Cache is not the all hail method.
i also found 386DX40 Systems with Cache with very slow memory Speeds.
Some MX Chipsets had 8Kb integrated into System Chipset and this was also already giving a good boost 😀
And also there good OPTI Boards that are very well engineered and run without any Cache almost a whopping 1Mb/s per Mhz throughput. (25Mhz CPU @ 23.9Mb/s..)

Why should a 386SX not benefit from RAM ?
Windows 3.1 would even benefit from 16Mbytes on a 286 System.

Congratulations on this Nice find, a very cool Motherboard 😀

matze79 wrote on 2021-07-05, 22:29:

Depends.. Cache is not the all hail method. i also found 386DX40 Systems with Cache with very slow memory Speeds. Some MX Chips […]
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Disruptor wrote on 2021-07-05, 14:27:

A 386/40 should have some cache.
Regardless whether DX or SX.

Depends..
Cache is not the all hail method.
i also found 386DX40 Systems with Cache with very slow memory Speeds.
Some MX Chipsets had 8Kb integrated into System Chipset and this was also already giving a good boost 😀
And also there good OPTI Boards that are very well engineered and run without any Cache almost a whopping 1Mb/s per Mhz throughput. (25Mhz CPU @ 23.9Mb/s..)

Why should a 386SX not benefit from RAM ?
Windows 3.1 would even benefit from 16Mbytes on a 286 System.

Congratulations on this Nice find, a very cool Motherboard 😀

My Zenith 286LP Plus is a 286/12 and performance almost the same as my old original 286/16. It runs MS Windows 3.1 with 8megs of ram just fine and dandy...😉 An introduction to Window 3.1 tutor told us the best thing you can do to a computer is give it as much ram as it would take.

matze79 wrote on 2021-07-05, 22:29:

Depends.. Cache is not the all hail method. […]
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Disruptor wrote on 2021-07-05, 14:27:

A 386/40 should have some cache.
Regardless whether DX or SX.

Depends..
Cache is not the all hail method.

Why should a 386SX not benefit from RAM ?

Congratulations on this Nice find, a very cool Motherboard 😀

I can agree ! A well built 386SX-40 cacheless board under average usage is as snappy as 386DX-25 with cache. And I really like those micro 386 AT boards, they are cute and quite funtional ! 😁
added: Here is one of mine: Re: 80386 BIOS image collection very similar and works well !

Caluser2000 wrote on 2021-07-05, 21:14:

It'll be around the equivilent of a Harris 286/2o in that regard. That is one reason my first x86 system was a 286/16 instead of a 386SX16.

Yeah I tossed a problematic large 386SX-16 board not long ago, was barely a match to my 286-12 or -16 "when it was working".

Oh, I noticed something interesting about this 386SX 40 motherboard, it has one sided tracks for CPU, chipsets and far fewer tracks on other side. And very few vias, that's very serious saving on drillings!

Cheers,

Interesting, take good photos and we can run a board up at a fab house and figure out which FPGA to copy the chipset with 🤣

... ... ...

Yah, 386SX16s just seem blah in general, I'd rather use a 286-12... mind you, I'd rather use a V20 than a 286-10 or below, they're just blah also. Must be something like the slack in the timings that the slower CPUs of a generation could really do without or something.

matze79 wrote on 2021-07-05, 22:29:

Why should a 386SX not benefit from RAM ?

There is very little software that can benefit from it on 386SX, most notably Windows 3.1. But back in the day Windows 3.1 wasn't particularly useful. I had it but I almost never started it. On 386SX the best use for extra memory is probably smartdrive.

386SX is too slow for games designed for early 486 which require 4-8MB memory. 386DX40 can handle some of those. But if one aims mainly for 286-386 games it will be ok.

It just depends on what you find useful.
Doing excel spreadsheets, using word.. Corel Draw all this benefits heavily.
Using a Scanner also quickly did exhaust memory.
And specially if switching between different Sessions.
Excel and Word with 4 megs was pain in the ass 🤭

But yes most games will fine with 4 megs.
I often found 2 megs not sufficient and I had Olivetti SX 25Mhz back then.
It was opening a entire new world going for 4 megs.

AlexZ wrote on 2021-07-06, 07:46:

matze79 wrote on 2021-07-05, 22:29:

Why should a 386SX not benefit from RAM ?

There is very little software that can benefit from it on 386SX, most notably Windows 3.1. But back in the day Windows 3.1 wasn't particularly useful. I had it but I almost never started it. On 386SX the best use for extra memory is probably smartdrive.

386SX is too slow for games designed for early 486 which require 4-8MB memory. 386DX40 can handle some of those. But if one aims mainly for 286-386 games it will be ok.

I used to have a 386SX laptop with Windows 3.0 and later 3.1, and it had only 2MB memory. I know I would literally KILL to have 4MB memory on it because running MS Works for Windows with 2MB memory was very painful. So really, I'd say don't generalize. Not everyone was using computers the same. I know there were people with 386 systems in the early 90s who would go online with Windows 3.1.

appiah4 wrote on 2021-07-06, 10:53:

I used to have a 386SX laptop with Windows 3.0 and later 3.1, and it had only 2MB memory. I know I would literally KILL to have 4MB memory on it because running MS Works for Windows with 2MB memory was very painful. So really, I'd say don't generalize. Not everyone was using computers the same. I know there were people with 386 systems in the early 90s who would go online with Windows 3.1.

I also used to have 386SX with 2MB memory so I know Windows 3.0 was barely usable. It didn't support large amount of virtual memory with low amount of physical memory and took very long to boot on that machine (~40s). It only became usable with 4MB RAM which is why I specifically mentioned it in my previous post. If someone wants to run historical software in Windows 3.0 then 4MB RAM is definitely needed, however this use case will likely be very rare. All I advocate is buying memory based on one's needs to keep prices down for those who need it.

BitWrangler wrote on 2021-07-05, 21:02:

Some of these late SX chipsets had an 8KB cache built in, enough to cache 16MB.

Can the MX chipset with 8kb really cache all 16MB? I thought it could only cache 8MB.

I don't personally know, that's what I've come across online. Historically I only ran SX boards with 4MB, maybe 8 a couple of times, recently, I've not had anything set up to confirm/deny.

The speed of the system also depends a lot on the chipset and waitstates. And with games also on the video card:

http://www.os2museum.com/wp/fast-unaccelerated-vga/
https://www.os2museum.com/wp/about-those-trident-vgas/
http://www.os2museum.com/wp/more-isa-vga-benchmarks/

Cached 386SX 20

Is this your board? Some test/benchmarks would be great 😉

Not sure how would cache improve performance on 20Mhz cpu.

386SX benefits from cache so much, ditto to 386DX with cache. I had compaq LTE 386s/20 which is a real 386SX 20 CPU with compaq custom chipsets one of them containing 8K cache. When I swapped 386SX for AMD 386SX 25 or more and changed crystal oscillator. Performed even faster.

Cheers,

Of course going from 20mhz to 25mhz will be faster...😉

I'm also in the "386SX doesn't need cache" camp. Especially not the 40MHz version. Sure, with cache it would be faster but frankly if you need faster you want a 40MHz DX with a decent mobo or even a 486DX2 for smooth gameplay in Doom (that or UMC 486 chip). I have ALI M1217 mobo that can run 50ns RAMs at 0WS setting, that thing pretty much catches up to 33MHz 386DX in NSSI benchmark. The mobo is small, simple, easy to repair, and doesn't have tons of complicated BIOS settings that mostly don't work anyway. So ideal for beginners or people who want/need a simple, rock-stable system that just works.

I never had a "fast" 20MHz+ 286 but somehow I don't belive such system would be much faster than 386SX. Sure, some instructions (like I/O for example) are slower on 386 due to new protection mechanisms like V86 mode or paging, but in general there should not be more than 10% difference even in 286-optimized code. Fast 286 mobos are rare, sometimes also pretty quirky, whereas 386SX at 33 or 40MHz are easy to fnd and work with. Also there's EMM386 for your UMB and emulated EMS needs, and some 386 games - while not butter smooth - will be playable on decent SX system. Like Ultima Underworld (especially with decent VGA or if you disable floor/ceiling texturing, like what Wolf3D does).

386SX was supposed to be cheap (and faster) replacement for 286, while also offering 32-bit CPU. Cache belongs on full-fat 386DX mobos, if you are trying to put it on SX you are doing it wrong.

I maxed out the memory with 16MB and changed the video card to a Paradise WD90C31 1MB video card. I also installed Windows 3.11. This makes for a very nice Windows 3.x computer with the upgraded memory and video accelerator:)