Stason's only lists memory configurations with all 4 simms being populated by the same type of module.

thanks for noting that.
now i am looking at another board that looks like this:

it has 8 simm slots and cache. is the empty socket at lower right corner for rapidcad/486dlc only, or would any 387 fpus fit in it?

Wow a cacheless 386DX ... must be a cheap board or something budget. Personally I wouldn't bother with it unless you are looking to build a pc that has fast 286 performance and 386 instructions... it has it's uses for sure but don't expect it to have any performance near a board with 128kb of cache.

noshutdown wrote:

we know that 386dx has 32bit fsb,

does that mean that they have only a 16bit dram bus? and how much performance does that hurt?

There are differences between 32-bit and FSB.

FSB is your Front Side Bus, and determines how frequently your system will cycle. On a 386 this can commonly be 33 MHz or 40 MHz, and lower system speeds.

32-bit, is your bandwidth, and determines how much data can either be addressed, read, written, copied, moved etc. Serial transmission is 1 bit at a time, parallel transmission is more than 1 bit at a time and was originally designed to speed things up faster than a mouse i.e. a LPT / dot-matrix printer. With the evolution of x68's, and parallel communication, CPU's could address and manipulate more bits at a time.

One of the most important steps being the 386... which is the worlds first 32-bit CPU! 😎 Addressing twice as many 1 bit locations as the 16-bit 286.

The best analogy I can think of is the motorways / highways... bandwidth is the number of lanes cars can drive on, FSB is the speed of the cars.

In answer to your question though... a 386DX will not boot / POST with only 16-bit accessible DRAM, it needs 32-bit to run. If you want to post a 386 system with only 16-bit DRAM you will need to find a 386SX. Operating with a 386SX instead of a 386DX will very much "hurt performance".

I hope this helps!

keropi wrote:

Wow a cacheless 386DX ... must be a cheap board or something budget. Personally I wouldn't bother with it unless you are looking to build a pc that has fast 286 performance and 386 instructions... it has it's uses for sure but don't expect it to have any performance near a board with 128kb of cache.

That board uses the MX chipset, which has 8kb of integrated cache. I've heard performance is not really hurt much by this. Despite having limited memory configurations, it should perform decently.

I have the same board, it's a Pinetech PT-321. It was a late 386 board, by then the 386 was "value" processor so they decided to save on SIMM slots. Unfortunately this made the memory configuration really inflexible. You must populate the 4 simm slots to make it work since the CPU FSB it's 32 bit wide so you can have 1MB (256kBx4), 4MB (1MBx4) or 16MiB (4MBx4) of memory installed on it (really weird). The MX chipset has 8KB of cache integrated so the manufactured saved on cache chips too 🙁

It's a very decent board, though. I have been used it for years without any hitch. Performance it's adequate. I have a MS-3134 board with 128KB of cache and both have very similar performance.

BTW my AMI BIOS is dated 11/11/91 and lacks the HDD autodetection feature (I think this feature was added on 06/07/92 AMI BIOS) Do your board have a more recent BIOS version?

dieymir wrote:

It's a very decent board, though. I have been used it for years without any hitch. Performance it's adequate. I have a MS-3134 board with 128KB of cache and both have very similar performance.

I would say (with my limited experience using MX chipset's) that they are pretty good... having said i've only worked with the single chip (83C409FC ) variant, the board also has 3 x VLB. The picture below shows the board as received (with a 486), but is now currently running with a 386 installed.

Would be interesting to see some benchmarks of the ISA board if anyone has?

OK if it has 8kb of cache then it will be ok-ish... 0kb of cache is really bad - clock speed doesn't really matter much or 32bit buses, they are all wasted
Here is a speedsys shot of a 286/EGA setup that is upgraded with a 33mhz 386sx kingston module - it has 16kb of cache (until it gets enabled performance is at slow 286/16 levels)

Is this with cache or not? Performance level on this screenshot is on level with 386SX-33.

With cache ofcourse. I cruised the early 90s with a cacheless 386sx20 - it was like a fast 286/16 at best...
I once upgraded said 386sx20 to a 486slc2/40 - the mhz boost was nothing, the only thing that made the difference was the 1kb of cache the 486slc has onboard - but 1kb is so small it only made a difference in benchmarks.
The upgraded 286/16 on the other hand is twice as fast now and you can really feel the boost.

noshutdown wrote:

i found they marked two simms as "bank0" while another two as "bank1". does that mean that they have only a 16bit dram bus? and how much performance does that hurt?

I think these were also available in 386sx versions, maybe that manual is for those?

keropi wrote:

With cache ofcourse. I cruised the early 90s with a cacheless 386sx20 - it was like a fast 286/16 at best...
I once upgraded said 386sx20 to a 486slc2/40 - the mhz boost was nothing, the only thing that made the difference was the 1kb of cache the 486slc has onboard - but 1kb is so small it only made a difference in benchmarks.
The upgraded 286/16 on the other hand is twice as fast now and you can really feel the boost.

Fast 286-16 is almost like 386SX-25.

I wasn't much better. I replaced fast 286-16 with 486slc-33. As I only replaced the motherboard, the rest stayed the same, like C&T 256kb VGA card, the new system behaved like 3% faster 🤣 After I changed the vga card for Trident 8900D, the little slc board really took of. Although only with 1kb cache it was on par with 386DX-40 or even better in some cases.

386_junkie wrote:

There are differences between 32-bit and FSB. […]
Show full quote

There are differences between 32-bit and FSB.

FSB is your Front Side Bus, and determines how frequently your system will cycle. On a 386 this can commonly be 33 MHz or 40 MHz, and lower system speeds.

32-bit, is your bandwidth, and determines how much data can either be addressed, read, written, copied, moved etc. Serial transmission is 1 bit at a time, parallel transmission is more than 1 bit at a time and was originally designed to speed things up faster than a mouse i.e. a LPT / dot-matrix printer. With the evolution of x68's, and parallel communication, CPU's could address and manipulate more bits at a time.

One of the most important steps being the 386... which is the worlds first 32-bit CPU! 😎 Addressing twice as many 1 bit locations as the 16-bit 286.

The best analogy I can think of is the motorways / highways... bandwidth is the number of lanes cars can drive on, FSB is the speed of the cars.

In answer to your question though... a 386DX will not boot / POST with only 16-bit accessible DRAM, it needs 32-bit to run. If you want to post a 386 system with only 16-bit DRAM you will need to find a 386SX. Operating with a 386SX instead of a 386DX will very much "hurt performance".

I hope this helps!

i know the 386dx would need 32bit data bus to function, but isn't the dram access handled by the chipset? so it could be possible if the chipset could divide a 32bit data into two 16bit dram operations, this would be very slow like the 386sx and also requires chipset support though.

dieymir wrote:

I have the same board, it's a Pinetech PT-321. It was a late 386 board, by then the 386 was "value" processor so they decided to save on SIMM slots. Unfortunately this made the memory configuration really inflexible. You must populate the 4 simm slots to make it work since the CPU FSB it's 32 bit wide so you can have 1MB (256kBx4), 4MB (1MBx4) or 16MiB (4MBx4) of memory installed on it (really weird). The MX chipset has 8KB of cache integrated so the manufactured saved on cache chips too 🙁

It's a very decent board, though. I have been used it for years without any hitch. Performance it's adequate. I have a MS-3134 board with 128KB of cache and both have very similar performance.

BTW my AMI BIOS is dated 11/11/91 and lacks the HDD autodetection feature (I think this feature was added on 06/07/92 AMI BIOS) Do your board have a more recent BIOS version?

i'll live with 4*4mb although that seems a bit tight for windows95, 32mb would surely be more preferable.
about the bios, the package is still on the way so i have yet to look into it, i hope it has a newer bios since the chips were all made in late 1994.
how should i setup hdd chs if i am going to use a 512mb ssd or sd2ide?

can anyone have a look at the second picture and give some ideas?

386_junkie wrote:

dieymir wrote:

It's a very decent board, though. I have been used it for years without any hitch. Performance it's adequate. I have a MS-3134 board with 128KB of cache and both have very similar performance.

I would say (with my limited experience using MX chipset's) that they are pretty good... having said i've only worked with the single chip (83C409FC ) variant, the board also has 3 x VLB. The picture below shows the board as received (with a 486), but is now currently running with a 386 installed.

Would be interesting to see some benchmarks of the ISA board if anyone has?

Wow, what the hell is that MX hybrid board? Are those two square chips cache modules? I wish there was a cleaner image.

noshutdown wrote:

386_junkie wrote:

There are differences between 32-bit and FSB. […]
Show full quote

There are differences between 32-bit and FSB.

FSB is your Front Side Bus, and determines how frequently your system will cycle. On a 386 this can commonly be 33 MHz or 40 MHz, and lower system speeds.

32-bit, is your bandwidth, and determines how much data can either be addressed, read, written, copied, moved etc. Serial transmission is 1 bit at a time, parallel transmission is more than 1 bit at a time and was originally designed to speed things up faster than a mouse i.e. a LPT / dot-matrix printer. With the evolution of x68's, and parallel communication, CPU's could address and manipulate more bits at a time.

One of the most important steps being the 386... which is the worlds first 32-bit CPU! 😎 Addressing twice as many 1 bit locations as the 16-bit 286.

The best analogy I can think of is the motorways / highways... bandwidth is the number of lanes cars can drive on, FSB is the speed of the cars.

In answer to your question though... a 386DX will not boot / POST with only 16-bit accessible DRAM, it needs 32-bit to run. If you want to post a 386 system with only 16-bit DRAM you will need to find a 386SX. Operating with a 386SX instead of a 386DX will very much "hurt performance".

I hope this helps!

i know the 386dx would need 32bit data bus to function, but isn't the dram access handled by the chipset? so it could be possible if the chipset could divide a 32bit data into two 16bit dram operations, this would be very slow like the 386sx and also requires chipset support though.

Interesting point/question. I don't ussually work with 386SX systems... They were a pointless endeavour aimed at home PC market and clipped pins of a cpu that could still address upto 24 lines but only had 16 pins to do so.

About the chipset... I have never seen or known one to switch between 16-bit and 32-bit operation. I have seen the switch between 386 / 486 CPU's ... But they are all 32-bit and have the hardware (address lines) to accomodate.

The only possible explanaition could be is that the manufacturer made the same board that could be made to accomodate either a 386SX or 386DX system. The chipset could possibly address upto 32-bit but only do 16 depending on config... to confirm you would best look at the datasheet.

Anonymous Coward wrote:

386_junkie wrote:

dieymir wrote:

It's a very decent board, though. I have been used it for years without any hitch. Performance it's adequate. I have a MS-3134 board with 128KB of cache and both have very similar performance.

I would say (with my limited experience using MX chipset's) that they are pretty good... having said i've only worked with the single chip (83C409FC ) variant, the board also has 3 x VLB. The picture below shows the board as received (with a 486), but is now currently running with a 386 installed.

Would be interesting to see some benchmarks of the ISA board if anyone has?

Wow, what the hell is that MX hybrid board? Are those two square chips cache modules? I wish there was a cleaner image.

Yea it's another 386/486 hybrid VLB board... I own quite a few, it's the flagship project... Nearly finished! Those are obscure cache modules yes, with space for more. Will look to take and send you a better pic.