jasa1063 wrote on 2021-07-04, 15:06:

I wanted to have a 386SX/40 in my retro PC collection, so I put together a system with the following specs: […]
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I wanted to have a 386SX/40 in my retro PC collection, so I put together a system with the following specs:

TD70AN motherboard
AMD 386SX/40 CPU
IIT 387SX/40 Math Coprocessor
4MB memory 60ns (4 x 1MB 30-pin SIMMs)
MicroLabs Ultimate TrueColor ET4000AX 1MB ISA video card
Goldstar Prime2c multi I/O card
Sound Blaster 16 CT4170 sound card
3Com Etherlink III 3C509B Ethernet card
CompactFlash to IDE adapter with 2GB CompactFlash Card
ISA ROM card with XTIDE universal BIOS for disk handling

Everything was working fine except the system time would not update when powered off. It has a new barrel battery, so I was bit stumped. I found pictures of the same motherboard online and I noticed they all had the two middle pins of the 4-pin connected labeled CN7/EXT BAT jumpered. When I jumpered those two pins it is now keeps time just fine. There is no cache on this motherboard so the performance is solely based on the speed of the memory and the latency. I have this tweaked to the fastest settings the BIOS allowed. Here are a few benchmarks:

Norton SI 8.0: 29.2

3DBench 1.0: 10.7

Topbench 0.40a
Score: 65
Memory: 182
Effect addressing: 111
Opcode exercise: 102
Vid adapter speed : 326
3DGame opcode exercise: 84

The pictures are from the seller I bought the board from on eBay. Overall I am very happy with this build.

I had something simular back in 1998 but it had a intel 386 plastic processor and a removable chip for 640kb ram. These were awesome because of the 1 chip memry meant less latency due to less traveling data i/o.

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..)

I'd really like to know more about this motherboard. 24MB/sec is basically the speed of external cache on most 40MHz 386DX boards.
Are you sure it isn't some kind of weird speedsys anomaly?

Actually, back in 1993 allot of 486 ISA motherboard were sold with only 64kb of cache too.
Even NEW ( $3000 ) OEM Multimedia 486 computers from IBM, Gateway, AST, and others were only sold with 64kb of cache.
And these were suppose to be multimedia computers with sound cards and CDROM drives.
They only came with 4mb of RAM.
128kb of cache is okay, 256kb of cache is the sweet spot. 512kb of cache offers minimal performance boost over 256kb.

My own 486-33 only had 64kb cache. 256kb is only marginally faster. It’s only useful if you need more than 16mb of ram.

Anonymous Coward wrote on 2021-07-17, 09:32:

My own 486-33 only had 64kb cache. 256kb is only marginally faster. It’s only useful if you need more than 16mb of ram.

You are right. There is only about a 3% to 5% performance boost when going from 64kb. To 256kb.
Does not make much of a difference in DOS game play on a 386 or 486 computer because you really need a
Pentium 75mhz CPU computer or higher for Good DOS game play that does not stutter or hesitate.

Intel486dx33 wrote on 2021-07-17, 09:18:

Actually, back in 1993 allot of 486 ISA motherboard were sold with only 64kb of cache too. Even NEW ( $3000 ) OEM Multimedia 486 […]
Show full quote

Actually, back in 1993 allot of 486 ISA motherboard were sold with only 64kb of cache too.
Even NEW ( $3000 ) OEM Multimedia 486 computers from IBM, Gateway, AST, and others were only sold with 64kb of cache.
And these were suppose to be multimedia computers with sound cards and CDROM drives.
They only came with 4mb of RAM.
128kb of cache is okay, 256kb of cache is the sweet spot. 512kb of cache offers minimal performance boost over 256kb.

It was very very expensive because of a ram chip manufacture literally went up in smoke. I would image this would be the main reason new systems ram was a bit on the low side back then.

1meg sticks of ram were around nz$100 at the time.

Caluser2000 wrote on 2021-07-17, 10:04:

Intel486dx33 wrote on 2021-07-17, 09:18:

Actually, back in 1993 allot of 486 ISA motherboard were sold with only 64kb of cache too. Even NEW ( $3000 ) OEM Multimedia 486 […]
Show full quote

Actually, back in 1993 allot of 486 ISA motherboard were sold with only 64kb of cache too.
Even NEW ( $3000 ) OEM Multimedia 486 computers from IBM, Gateway, AST, and others were only sold with 64kb of cache.
And these were suppose to be multimedia computers with sound cards and CDROM drives.
They only came with 4mb of RAM.
128kb of cache is okay, 256kb of cache is the sweet spot. 512kb of cache offers minimal performance boost over 256kb.

It was very very expensive because of a ram chip manufacture literally went up in smoke. I would image this would be the main reason new systems ram was a bit on the low side back then.

1meg sticks of ram were around nz$100 at the time.

Cache was not that expensive back in 1993 but novice computer users did not know what they needed so they trusted the computer
Companies recommendations. But these computer component sellers were trying to make money any way they could so they would sell you
A bare ISA motherboard and then sell you the add on components.
But I don’t think computer builder stores knew much more than the novice computer user as to what the performance values
Would be for each product. They just wanted to make money.
They were not really trying to sell you the best performance value computer build.