yes
no
just dont do it if its a cirrus logic VGA, upgrading ram does nothing for them

rasz_pl wrote on 2022-08-03, 21:08:

yes
no
just dont do it if its a cirrus logic VGA, upgrading ram does nothing for them

Thanks for the response. This is for an S3 card.

I got a good sized lot of really cheap ram chips from the people's republic, but when installed they cause a bunch of screen artifacts. Curios if it's a card problem or all these chips are simply garbage.

It could be either one. Invisible minor corrosion/film/etc in the sockets can cause that. Bad card or bad memory chips can too.
Try Qtip and ISO Alcohol in the sockets and see if it helps. Can you post a picture of the memory chips ?

effy wrote on 2022-08-03, 20:38:

Does anybody know if I should be able to upgrade the video memory of an old VGA card (in this case they are SOJ-40 sockets) with different model memory chips, if they are the same type? (256 x 16 edo 5v). Does it matter if the access time is faster than what is soldered on board?

Be careful. You already quoted some relevant properties (EDO vs. FPM; 5V vs. 3.3V), which is good. But you didn't quote whether your upgrade chips are "dual CAS" or "dual WE". S3 cards generally need "dual CAS" chips. Check the datasheet. Dual WE chips have two write enable inputs ("WEL" / "WEH") for the "low" and "high" byte, whereas Dual CAS chips have just a single WE input, but two CAS inputs ("CASL"/"CASH" or "CAS0"/"CAS1" or "LCAS"/"UCAS").

mkarcher wrote on 2022-08-07, 18:07:

effy wrote on 2022-08-03, 20:38:

Does anybody know if I should be able to upgrade the video memory of an old VGA card (in this case they are SOJ-40 sockets) with different model memory chips, if they are the same type? (256 x 16 edo 5v). Does it matter if the access time is faster than what is soldered on board?

Be careful. You already quoted some relevant properties (EDO vs. FPM; 5V vs. 3.3V), which is good. But you didn't quote whether your upgrade chips are "dual CAS" or "dual WE". S3 cards generally need "dual CAS" chips. Check the datasheet. Dual WE chips have two write enable inputs ("WEL" / "WEH") for the "low" and "high" byte, whereas Dual CAS chips have just a single WE input, but two CAS inputs ("CASL"/"CASH" or "CAS0"/"CAS1" or "LCAS"/"UCAS").

Good info thanks. I had compared the datasheets and the pinouts for both looked the same. I'll have to look them over again and specifically look for this.

Horun wrote on 2022-08-07, 15:54:

It could be either one. Invisible minor corrosion/film/etc in the sockets can cause that. Bad card or bad memory chips can too.
Try Qtip and ISO Alcohol in the sockets and see if it helps. Can you post a picture of the memory chips ?

Both the card and chips look quite clean but I can give them a once over. I tried all of the sockets and each memory chip. This card has 6 of them!

The artifacting is significant, complete screen really. Interestingly if I only populate the sockets that are not inline with the onboard memory, display is fine until you try a higher resolution, which makes sense. If I populate the ones inline with the onboard, it's as soon as you boot.

Here's the two datasheets
Onboard:
https://pdf1.alldatasheet.com/datasheet-pdf/v … C16258HK40.html

New:
https://www.digchip.com/datasheets/parts/data … 56A-25J-pdf.php

effy wrote on 2022-08-08, 14:59:

Here's the two datasheets Onboard: https://pdf1.alldatasheet.com/datasheet-pdf/v … C16258HK40.html […]
Show full quote

Here's the two datasheets
Onboard:
https://pdf1.alldatasheet.com/datasheet-pdf/v … C16258HK40.html

New:
https://www.digchip.com/datasheets/parts/data … 56A-25J-pdf.php

They are in fact both "dual CAS" chips. So you did buy chips that ought to work on that card. Can you tell us what type of S3 chip your card has (I guess a Trio64, Trio64/V+ or Trio32)?

It's an S3 Trio64V2/DX

effy wrote on 2022-08-08, 19:31:

It's an S3 Trio64V2/DX

OK, I get it. You are supposed to fit the sockets "above" (further away from the PCI slots) the two soldered chips first, those are labelled "U4" and "U6" (that's why it names these two positions in the "2nd MB" comment on the card). They complete the "half-filled bank" made of the two soldered chips U8 and U10. A full memory bank consists of 64 bits. Each of these chips contributes 16 bits, so a complete bank uses 4 chips. The only supported configurations for that card are: Memory as is (1MB, lower performance in Windows), two add-on chips in U4 and U6 (2MB, full performance) and six add-on chips (4MB, same performance). Every other configuration is unsupported. Can you show a picture of a true-color mode with artifacts when you just fill U4 and U6?

mkarcher wrote on 2022-08-08, 19:56:

effy wrote on 2022-08-08, 19:31:

It's an S3 Trio64V2/DX

OK, I get it. You are supposed to fit the sockets "above" (further away from the PCI slots) the two soldered chips first, those are labelled "U4" and "U6" (that's why it names these two positions in the "2nd MB" comment on the card). They complete the "half-filled bank" made of the two soldered chips U8 and U10. A full memory bank consists of 64 bits. Each of these chips contributes 16 bits, so a complete bank uses 4 chips. The only supported configurations for that card are: Memory as is (1MB, lower performance in Windows), two add-on chips in U4 and U6 (2MB, full performance) and six add-on chips (4MB, same performance). Every other configuration is unsupported. Can you show a picture of a true-color mode with artifacts when you just fill U4 and U6?

Hey I really appreciate your time spent helping me with this.

So I didn't really pay attention to the fact that the sockets might not be in a row but up and down, when not fully populated.

I have tried it with U4 and U6 populated only and I am not seeing any artifacts at 800x600 and 32bit color and 75hz which I wasn't able to set before with only 1mb.

I tried populating all 6 again and, surprisingly, there's actually far less artifacts, but you can see ghosting and such now. Before it was almost completely snowy with artifacts when fully populated. It's possible one of these cheapo chips is bad, I'll try each one individually in the U4/U6 configuration to check. Good progress though I think.

Ok so I think all these chips should be ok. I had intermittent issues with every chip while going through them, some not detecting at all. I went back to Horun's suggestion of cleaning and gave them a good clean with contact cleaner (and not normally something I'd do but a quick once-over with some very fine grit sandpaper I use for polishing in other hobbies).

Seems that did the trick. The overall artifacts I believe now were due to some chips not detecting at all and therefore not having a proper configuration when all chips were installed. Then when i tried just two chips, I didn't realize they needed to be in U4/U6, so same full screen artifacts.

Now I've got all 6 sockets populated and no artifacts. 1024x768 true color works with the 4mb total.

Thanks again for everyone's help!