Just throwing in an idea: memory and cache timings.
Your DX4 results make sense, and you're right, the 5x86 should be capable of 70+ with this vga

from my understanding a Intel dx4 does perform faster then amd dx4 however a dx4 133 amd which is a 5x86 should still have a good edge over a Intel dx4 100 but the 5x86 might be running a slower divider on the pci bus in the bios, play around with the pci divider option, cache timings make a difference too. What about internal cache write through or write back if your bios/board supports

There might be a possibility that PCI clock is divided by 2. Check the jumper configuration.

Thanks for the suggestions, guys.

I just upped the bus speed to 40 MHz so the CPU is now running at 160 MHz.

With this CPU speed I get 67.3 FPS in 3DBENCH2, so just barely outperforming the DX4... With a 60% higher CPU clock, higher bus speed, and PCI graphics. I don't think this is right.

I get 10.7 FPS in Quake, 13.4 in PC Player benchmark and 2134 gametics/2113 realtics in Doom. All of these seem low-ish to me.

Cache is write-back. I tried replacing all the RAM with 60ns modules (it had a mix of 60 and 70) and that does nothing. I also tried switching out the Matrox for an ARK2000PV and get the same results, so it's not the graphics card itself that's slow.

I've got what seems like optimal memory and cache timings in the BIOS, even if I switch it to manual there are no faster settings:

So at this point it feels like the PCI bus is the bottleneck; I'm leaning towards The Serpent Rider's suggestion: there are no PCI bus speed options in the BIOS setup so I'll have to check for jumpers. 😀

Auto configuration = Disable
DRAM speed = Fastest
DRAM Write Cycle = 0WS
DRAM Write CAS Pulse = 0 CCLK
CPU Burst Write = Enable
Cache Write Cycle = lowest (0 or 1)
Cache Burst Read Cycle = lowest (0)
L2 Cache/Dram cycle WS = lowest (0 or 1)

This should speed it up big time. You shoult get around 90FPS.

kixs wrote:

Auto configuration = Disable DRAM speed = Fastest DRAM Write Cycle = 0WS DRAM Write CAS Pulse = 0 CCLK CPU Burst Write = Enable […]
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Auto configuration = Disable
DRAM speed = Fastest
DRAM Write Cycle = 0WS
DRAM Write CAS Pulse = 0 CCLK
CPU Burst Write = Enable
Cache Write Cycle = lowest (0 or 1)
Cache Burst Read Cycle = lowest (0)
L2 Cache/Dram cycle WS = lowest (0 or 1)

This should speed it up big time. You shoult get around 90FPS.

Hey kixs! This is the CPU I recently bought from you on Amibay, by the way, maybe you already realized 'cause of the username 😉

I realize now that the auto settings were not optimal, sorry.

The lowest it goes is:

DRAM Write Cycle: 0 WS
DRAM Write CAS Pulse: 1 CCLK
Cache Write Cycle: 2 CCLK
Cache Burst Read Cycle: 1 CCLK
L2 Cache/DRAM Cycle WS: 2 CCLK

Can't select any lower values, they're not there.

Unfortunately, with these lowest settings the board will not boot past the memory test. Not even with 60ns RAM. Not at 133 Mhz either.

Hi 😀

This can happen. Try increasing DRAM Write cycle to 1 WS.

Best I can do is:

DRAM Speed: Faster (fastest crashes even with 1 wait state)
DRAM Write Cycle: 0 WS
DRAM Write CAS Pulse: 2 CCLK (1 crashes no matter what)
CPU Burst Write: Disable (Enable crashes even with the rest at auto)

Cache settings are as low as they will go, 2/1/2.

With these settings the machine boots and gets 82.9 FPS, so a significant improvement at least... Why does "memory speed: fastest" crash? Do I need better RAM? Or is the motherboard just not so great?

EDIT: is it possible that performance will suffer if you use EDO RAM in a board designed for FPM? Because I think some of the modules I'm using are actually EDO RAM, and the board takes them, but could that pose a problem?

EDIT 2: as far as I can tell there are no (documented) jumpers that divide the PCI bus speed. No settings in setup either. So I guess the PCI bus should be running at 40 MHz now? Is there any way to test the PCI bus speed with software?

Always use FPM, only a few motherboards support EDO but don't take any advantages with it. My guess would be the motherboard can't take it. You can always check with other memory modules if you have any spares. Try with only one installed module.

Check what is the model of your Soyo motherboard. Maybe I have it and can check the settings.

kixs wrote:

Always use FPM, only a few motherboards support EDO but don't take any advantages with it. My guess would be the motherboard can't take it. You can always check with other memory modules if you have any spares. Try with only one installed module.

Check what is the model of your Soyo motherboard. Maybe I have it and can check the settings.

It's an 030H2, seems to be quite a rare model:

https://stason.org/TULARC/pc/motherboards/S/S … -SY-030G-H.html

I realize EDO memory has no advantages in a board that doesn't explicitely support it, but the board runs stable otherwise so I was just mainly asking if EDO RAM in "FPM mode" so-to-speak runs identically to a real FPM module or if it can affect memory timings.

I'm going to check if I can get better timings with a known-good 60 ns real FPM module I have in one of my other 486 system later. Thanks for the help so far.

I didn't see a setting for the L1 cache. Is the 5x86 running write back or write through?

Anonymous Coward wrote:

I didn't see a setting for the L1 cache. Is the 5x86 running write back or write through?

L1 and L2 cache are enabled and working and cache is running in write-back mode.

EDIT:

einr wrote:

I'm going to check if I can get better timings with a known-good 60 ns real FPM module I have in one of my other 486 system later.

With this RAM, I can go "Faster" with 0 wait states or "Fastest" with 1 wait state. Before, "Fastest" was not possible even with wait states. Both settings seem to yield roughly the same result, at least in 3DBENCH2. I guess this board simply will not go faster than this, no matter what RAM is installed.

einr wrote:

Hey all, […]
Show full quote

Hey all,

DX4 specs (gets 67 fps):
M Technologies VLB motherboard, SiS 471 chipset
Intel DX4/100 (3x33)
16 MB FPM RAM
256K L2 cache
S3 805 2MB VLB

You know what, i found one of these SY-030H2 boards for 3 dollars that included an amd 100mhz cpu.
it looks nice, PCI; ISA, not vLB tho. And no support for AMD 133mhz cpu.

This board is so rare, only 1 website on google had information about it. wayback machine on soyo site from 1996 didnt even list the motherboard.
I spent some time with it and refused to boot over and over, until i used FPM ram and booted right away, seems like EDO was not supported.
then launched doom and speed was crappy, but then i remembered that some motherboards need turbo switch jumpered, so i jumpered turbo and speed was great.

doom 1 timedemo 3863 gametics on 3761 realtics

speed is nice compared to other 486 boards i had. where you able to setup correctly amd586 133mhz'?

SETBLASTER wrote:

You know what, i found one of these SY-030H2 boards for 3 dollars that included an amd 100mhz cpu. it looks nice, PCI; ISA, no […]
Show full quote

einr wrote:

Hey all, […]
Show full quote

Hey all,

DX4 specs (gets 67 fps):
M Technologies VLB motherboard, SiS 471 chipset
Intel DX4/100 (3x33)
16 MB FPM RAM
256K L2 cache
S3 805 2MB VLB

You know what, i found one of these SY-030H2 boards for 3 dollars that included an amd 100mhz cpu.
it looks nice, PCI; ISA, not vLB tho. And no support for AMD 133mhz cpu.

This board is so rare, only 1 website on google had information about it. wayback machine on soyo site from 1996 didnt even list the motherboard.
I spent some time with it and refused to boot over and over, until i used FPM ram and booted right away, seems like EDO was not supported.
then launched doom and speed was crappy, but then i remembered that some motherboards need turbo switch jumpered, so i jumpered turbo and speed was great.

doom 1 timedemo 3863 gametics on 3761 realtics

speed is nice compared to other 486 boards i had. where you able to setup correctly amd586 133mhz'?

Yeah, I have a jumper on the turbo.

The Am5x86 is running fine in my board at 160 MHz, the board doesn't officially support it but then again it doesn't need to. Set the jumpers to Am486DX2 (as per this page) and 3.45 volts.

BIOS will recognize it as an "Enhanced AMD 486DX4-S" and incorrectly report the speed as 120 MHz instead of 133 at stock speeds, but that's just a display error, it runs at the correct speed. At 160 MHz it will show 150 MHz but, again, it actually runs at 160 and works great.

I made a series of rambly videos about fixing and building a machine around this board if you're interested: https://www.youtube.com/channel/UChGmdVfj20P9KGV2wTJ6zYQ

The second half of the latest video includes some benchmarks and BIOS tweaks and demos of the board running games at 160 MHz.