Orientation of chips on modules is never a relevant factor for compatibility.

What does matter:
- module type (72p SIMM, 168p DIMM)
- voltage (5V, 3.3V)
- memory standard (FP, EDO, SDRAM)
- memory type (unbuffered, bufffered, registered)
- speed rating (in ns)
- chip density (in Mbps)
- number of chips

Now, if I'm not mistaken the M577 is a board with a Via MVP3 chipset that can have both 72p SIMM and 168p DIMM slots, but they aren't always populated. MVP3 supports EDO SIMMs and DIMMs and SDRAM DIMMs in chip densities up to 128Mb, but only on unbuffered modules. It can run the memory bus asynchonously, so 100MHz RAM with 66MHz CPU or vice versa. 100MHz requires 7ns SDRAM, 66MHz will work with 10ns SDRAM or 60ns EDO. Basically the MVP3 is a slut and anything that can work will work. But it's not working for you.

So:
- confirm that this is really an M577 with MVP3 chipset - and which memory slots are present on your board
- confirm specs of the DIMMs you're using. Please take care not to mix up mb and MB (m=milli, M=Mega; b=bit, B=Byte).
- explain what you mean by that other kind of "stick". Maybe post some pics...

Since it might help and it shouldn't hurt, I'd update it to the last BIOS if you haven't already, so here's the page Jan Steunebrink's patched BIOS: http://web.inter.nl.net/hcc/J.Steunebrink/k6plus.htm

hello, the 2 sticks on the left are the ones that this motherboard did recognize, but they have low capacity, the sticks on the right are the ones i tried and did not post (all of them have chips on both sides)

this second picture is about all my 128mb sticks i have that are pc133. that i will have to try once i get some free time.
the ones on the left are single sided, and the ones on the right are double sided

try that bios update too. my board had issues once and after updating it worked

In some cases, there is a layer of oxidation on the contacts of memory modules, thanks to which the board does not detect them. Then it helps to wipe contacts with ordinary pencil rubber (rubber eraser).

BLockOUT wrote on 2021-04-20, 00:03:

hello, the 2 sticks on the left are the ones that this motherboard did recognize, but they have low capacity, the sticks on the […]
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hello, the 2 sticks on the left are the ones that this motherboard did recognize, but they have low capacity, the sticks on the right are the ones i tried and did not post (all of them have chips on both sides)

The ones that do work are clear: DIMMs with 4Mx4=16Mb chips; 16 of those makes 32MB. They are being detected correctly. They're 10ns chips, so rated to max 100MHz (maybe just 66MHz)

I'm afraid the pics of the ones that don't aren't good enough for reading the actual chips themselves on the others, but if they have 16 chips, they look like 8Mx8 chips (64Mb), which should be perfectly fine. Small chance they may have 16Mx4, which are out-of-spec, but brands like Micron and Infineon tend to stick to standards, so that's highly unlikely.

They do look a bit dirty, so I second the suggestion to clean the pins. Just get a little rubber and rub it along the pins on both sides of the DIMMs. Blow off any residue, then give them a try.

this second picture is about all my 128mb sticks i have that are pc133. that i will have to try once i get some free time. the o […]
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this second picture is about all my 128mb sticks i have that are pc133. that i will have to try once i get some free time.
the ones on the left are single sided, and the ones on the right are double sided

The 128MB DIMMs with 8 chips can only have 128Mb chips with 16Mx8 architecture. They are definitely OK for the MVP3 memory controller. The Micron and Samsung DIMMs should be excellent quality. There again, give them a clean.

One good thing to do is take a known-good board to test the DIMMs in. If the DIMMs are dead, no surprise that they don't work on your M577.

dionb wrote on 2021-04-20, 08:22:

I'm afraid the pics of the ones that don't aren't good enough for reading the actual chips themselves on the others, but if they have 16 chips, they look like 8Mx8 chips (64Mb), which should be perfectly fine. Small chance they may have 16Mx4, which are out-of-spec, but brands like Micron and Infineon tend to stick to standards, so that's highly unlikely.

They do look a bit dirty, so I second the suggestion to clean the pins. Just get a little rubber and rub it along the pins on both sides of the DIMMs. Blow off any residue, then give them a try.

Spot of image editing, I think all three of the right-hand ones are IBM 33L3074, 128MB PC133-333 (Infineon one looks like -520 as well), 16Mx64. Searching on that IBM part numbers got me a better photo of a Hyundai part with HY57V658020BTC 75 chips, which has a description of 133 MHz 4Bank × 2M x8 SDRAM. So, as you said, 8Mx8 chips.

A copy of the manual for the M577 . Probably not very helpful, unfortunately .

https://web.archive.org/web/20041107132906/ht … 00/m577v30w.pdf

EDIT : or something similar to the M577 . See https://web.archive.org/web/20040910080354/ht … cchips/aka.html
"Example: The PM 9900 from Amptron has no mouseport and no PS/2 simms, but it is otherwise identical to the M577."

So I had this same problem on my M577 (aka Amptron PM-9900) recently and it turned out for me that the ram was not sitting correctly. I swear I’ve never had this problem of difficulty getting RAM installed in 2+ decades, yet here we are. It was so extremely hard to get it to sit. And then when I did manage to get it to clip, well, it wouldn’t boot. Turns out the RAM was not making contact in the middle. Solution was to take the board out and install Ram while holding the board from the bottom applying an extreme amount of pressure until all contacts on the RAM are in. Unfortunately I have to do it again later because I installed PC133 modules but the board does not support above 100fsb.

Zeerex wrote on 2022-05-21, 03:25:

So I had this same problem on my M577 (aka Amptron PM-9900) recently and it turned out for me that the ram was not sitting correctly. I swear I’ve never had this problem of difficulty getting RAM installed in 2+ decades, yet here we are. It was so extremely hard to get it to sit. And then when I did manage to get it to clip, well, it wouldn’t boot. Turns out the RAM was not making contact in the middle. Solution was to take the board out and install Ram while holding the board from the bottom applying an extreme amount of pressure until all contacts on the RAM are in. Unfortunately I have to do it again later because I installed PC133 modules but the board does not support above 100fsb.

I've heard this before about PCChips motherboards; apparently it's caused by their use of very thin printed circuit boards to cut costs.

I've used PC133 memory without issue on many motherboards that used a lower FSB - what exactly is the issue you're having?

Repo Man11 wrote on 2022-05-21, 03:30:

I've heard this before about PCChips motherboards; apparently it's caused by their use of very thin printed circuit boards to cut costs.

I've used PC133 memory without issue on many motherboards that used a lower FSB - what exactly is the issue you're having?

Yes, the board flexes a good amount which does not help. But otherwise it’s a sturdyish, stable and peppy board (the 1mb cache appears to help) - pretty surprised by it given the bad reputation of PCChips. No issues with PC133 I just want to save those sticks for a build that can use them at that frequency.

BLockOUT wrote on 2021-04-19, 12:29:

I was trying to upgrade the memory on one of these boards, pcchips m577 when booted the machine it had 32mb and i wanted more. […]
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I was trying to upgrade the memory on one of these boards, pcchips m577
when booted the machine it had 32mb and i wanted more.

Took out a bunch of 128mb sticks from different brand, and i had no luck, no post (sticks had memory on both sides)
placed some some 128mb sticks (with memory on one side ) and no luck, did not post either.

what i saw was that the motherboard kind of liked another stick of memory (one that has the memory placed horizontally on the memory pcb and not vertically, vertically is what you se more common)

What kind of memory should be used with this board? im using high quality brand memory and it doesnt even boot. The board is set to 3.3v in the jumper.

It often matters if the sticks that go in yhese are simgle or dual sided, the single sided stuff has much better luck on these. I have seen some of these boards (with this chipset) very strongly prefer to be populated with single sided memory.

I’ve never noticed that the orientation of the chip mattered as others noted. More likely the chip is actually different or the circuit or spd is different.

However, the single sided thing has exceptions:
I have sucessfully populated my mvp3 with 640mb of pc 150 ram consisting of two double sided modules and one single and have no issues. In fact I still have it set up that way.

You’ll often find though that the best setup for these boards is 384mb or less of single sided pc133-pc166 memory at the lowest timings.

As for what specific sticks will work, try them one at a time, but try the single sided ones first.

Late to reply but i was unfortunate enough to have this cheap mobo in my rig in 1999.
I could only max out the RAM (not in 1999 because it was darn expensive at the time) to 3*128 MB with single sided PC100 or PC133.
If one was double sided, then only one other single sided would work.
There were no 256 MB PC100/133 single sided at the time (if that ever existed) and i could never achieve more than 384 MB but that was a lot for Win95 to Win98SE anyway.