Why not run speedsys or cachechk ?

I'm not sure whether this chipset is able to do an ideal 2-1-1-1 burst on 40 MHz with a single SRAM bank...
You have 256 kB L2 cache in a single bank with 4 64kx8 modules + 1 32kx8 tag.

theelf wrote on 2024-04-29, 19:51:

Hi, im building a 486 PC for my personal collection, and i chose a AB-PB4 motherboard. Is not a bad one, exept some problems w […]
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Hi, im building a 486 PC for my personal collection, and i chose a AB-PB4 motherboard. Is not a bad one, exept some problems works very good, and support my Cyrix 5x86 100mhz CPU without problem

One thing i really curious is about L2 cache, now have 256kb

702e1432-adf0-4d9d-8446-d8cdb44a03e6.jpg

I did a lot of test and i found the speed gain is almost nothing, for example, Doom without L2 cache give me 67.2fps in a timedemo, and 68.1 in same timedemo with cache enabled! is like nothing! 3dbench, pcbench, quake, etc give me the same, almost nothing difference

im surprise, because in other 486 motherboards i have, L2 cache give me from 10 to 15% differences

Anyways i decide to disable L2 cache, because sadly did not work well if i overclock cpu to 120mhz, the system hang in boot or loading a game or program, but still want to talk about what can happen to the cache... and one more thing, someone knows if a faster cache will work fine wth CPU at 120mhz?

thanks

I am quite sure, that there is no "Western" brand for SRAMs, so it must be fake cache.
The tag ram is not visible (way too blurry) on the picture.

weedeewee wrote on 2024-04-29, 19:58:

Why not run speedsys or cachechk ?

Hi, yes i already did cachechk, and say L2 cache is in working order

L1 cache is 16kb and 204.7mb, L2 is 256KB and 77.3mb, and main memory is 49.1mb/s

CoffeeOne wrote on 2024-04-29, 20:29:

I am quite sure, that there is no "Western" brand for SRAMs, so it must be fake cache.
The tag ram is not visible (way too blurry) on the picture.

Hi, the tag say 71256 SA15TP E9533P

Sadly i dont have cache on other motherboards that are -15, the fastest one i have is -20 and at 120mhz not even boot, but like i say to weedeewee i think is real because cachechk can test it

Disruptor wrote on 2024-04-29, 20:27:

I'm not sure whether this chipset is able to do an ideal 2-1-1-1 burst on 40 MHz with a single SRAM bank...
You have 256 kB L2 cache in a single bank with 4 64kx8 modules + 1 32kx8 tag.

I was thinking about this, because i use 2-1-1-1 and 40x3 for 120. If i use 3-1-1-1 L2 works fine, but speed penalty is too much

theelf wrote on 2024-04-29, 20:45:

Is there anything special about the first ISA? slot next to the PCI slot ? the manual on theretroweb doesn't even seem to mention it. Aside from it sharing the same slot on the case as the third PCI slot.

weedeewee wrote on 2024-04-29, 20:57:

theelf wrote on 2024-04-29, 20:45:

Is there anything special about the first ISA? slot next to the PCI slot ? the manual on theretroweb doesn't even seem to mention it. Aside from it sharing the same slot on the case as the third PCI slot.

Is a PISA, can be a PCI or a ISA or have a riser for what i know

theelf wrote on 2024-04-29, 21:08:

weedeewee wrote on 2024-04-29, 20:57:

theelf wrote on 2024-04-29, 20:45:

Is there anything special about the first ISA? slot next to the PCI slot ? the manual on theretroweb doesn't even seem to mention it. Aside from it sharing the same slot on the case as the third PCI slot.

Is a PISA, can be a PCI or a ISA or have a riser for what i know

Can you post a photo of the underside of the motherboard ?

weedeewee wrote on 2024-04-29, 21:10:

theelf wrote on 2024-04-29, 21:08:

weedeewee wrote on 2024-04-29, 20:57:

Is there anything special about the first ISA? slot next to the PCI slot ? the manual on theretroweb doesn't even seem to mention it. Aside from it sharing the same slot on the case as the third PCI slot.

Is a PISA, can be a PCI or a ISA or have a riser for what i know

Can you post a photo of the underside of the motherboard ?

Sure, tomorrow i will post pictures,right now is late and no light

Disruptor wrote on 2024-04-29, 20:27:

I'm not sure whether this chipset is able to do an ideal 2-1-1-1 burst on 40 MHz with a single SRAM bank...
You have 256 kB L2 cache in a single bank with 4 64kx8 modules + 1 32kx8 tag.

With the right chips, yes, it can.
It's a fast board too, though the M1489 chip has two steppings of which the older one is faster at video access (or anything involving PCI, I guess). I have both and for a while I didn't understand why they perform differently...

Thanks, I guess it's likely just an ISA connector in an EISA connector color 😀

alvaro84 wrote on 2024-04-29, 21:24:

Disruptor wrote on 2024-04-29, 20:27:

I'm not sure whether this chipset is able to do an ideal 2-1-1-1 burst on 40 MHz with a single SRAM bank...
You have 256 kB L2 cache in a single bank with 4 64kx8 modules + 1 32kx8 tag.

With the right chips, yes, it can.
It's a fast board too, though the M1489 chip has two steppings of which the older one is faster at video access (or anything involving PCI, I guess). I have both and for a while I didn't understand why they perform differently...

Hi, is not a bad board I have a VIA and UMC motherboards and they are slow with same cpu than the ali, exept some minor problems, im very happy with this motherboard

I read exist -10 cache ram, but i think must be impossible to find right now

theelf wrote on 2024-04-29, 22:11:

I read exist -10 cache ram, but i think must be impossible to find right now

I just use regular -15 chips, though not every single one of them can do it. I tend to use 96/late 95 Winbond and UMC chips from the 512kbit variety, they tend to work just fine at 40MHz 2-1-1-1 in several different boards here, should they be single or dual bank ones. OTOH my only 1Mbit set (also 15ns) definitely falls short here.

L2 cache can indeed hamper your performance with high overclocking. Especially on late 486 motherboards with EDO support, where you can do 50-66 Mhz FSB pretty easily without adding wait states to memory.

486 board with UMC 8881E/8886B: The winner is: EDO without L2 (if your only other option is L2 at 3-2-2-2)

Where did you buy the L2 cache? I bought some from Ali some time ago and they were working but were slower then advertised. Used some acetone and they were clearly rebadged. Got my money back from Ali in the end.

The Serpent Rider wrote on 2024-05-02, 07:22:

L2 cache can indeed hamper your performance with high overclocking. Especially on late 486 motherboards with EDO support, where you can do 50-66 Mhz FSB pretty easily without adding wait states to memory.

486 board with UMC 8881E/8886B: The winner is: EDO without L2 (if your only other option is L2 at 3-2-2-2)

Ok, yes, after some test i can confirm, at least in my motherboard AB-PB4 and with Cyrix 5x86 at 100mhz - 33mhzx3, L2 cache is almost useless. I tried 128 and 256kb different cache ram, from other motherboards and the speed difference in from imperceptible to none

I have a IBM PS/1 486 DX4 and cache make a big difference, a 486DLC and same, but here is like cache did nothing, and i can confirm the cache i test is working fine in other motherboards

maybe i will find new cache that works with 40mhz bus some day and test again

alvaro84 wrote on 2024-05-02, 06:57:

theelf wrote on 2024-04-29, 22:11:

I read exist -10 cache ram, but i think must be impossible to find right now

I just use regular -15 chips, though not every single one of them can do it. I tend to use 96/late 95 Winbond and UMC chips from the 512kbit variety, they tend to work just fine at 40MHz 2-1-1-1 in several different boards here, should they be single or dual bank ones. OTOH my only 1Mbit set (also 15ns) definitely falls short here.

Sadly I only one -15 set, all others are -20 and both fails in 2-1-1-1 and 40mhz in my PB4. Shame! hope i will find new cache soon to test

Yoghoo wrote on 2024-05-02, 07:54:

Where did you buy the L2 cache? I bought some from Ali some time ago and they were working but were slower then advertised. Used some acetone and they were clearly rebadged. Got my money back from Ali in the end.

In my case,in spain, i just found more cheap to buy motherboards than order to aliexpress