Get 2 double sided modules with 8 chips on each side, for 2 times 64MB = 128MB

CoffeeOne wrote on 2021-05-29, 17:04:

Get 2 double sided modules with 8 chips on each side, for 2 times 64MB = 128MB

Like https://www.ebay.it/itm/333966519804 ?

No.
As I wrote, likelyhood is higher that it works, when you find double sided modules (with 16 chips on each module).

EDIT:
Is the working module (the 32MB one) double sided? Double sided means that is has chips on both sides.

If it is single sided, then you should try to find double sided 64MB sticks in my opinion.
But when the working module is already a double sided one, then maybe just try to find a similar one, and just have 64MB.

This technical manual?
http://ps-2.kev009.com/pccbbs/commercial_desk … op/d4as3tim.pdf

Not impressed by that manual. It seems exhaustive, up to descriptions of every pin on every connector, but leaves out a lot regarding memory.

First up- one thing included in the tables for cache, but not mentioned in the memory bit: the i430VX chipset can only cache 64MB. Everything over that will be uncached, so 128MB will be slower than 64MB, unless you actually fully use 64MB and start thrashing to virtual memory. If you want to run period-correct games that perform well on a P166MMX, you really don't need more than 64MB.

Then regarding the modules: the i430VX was the first SDRAM-supporting chipset and in retrospect it is very choosy about its RAM. IBM could/should have given exact specs required. "PC66" is the least relevant part: the speed rating of a DIMM indicates how fast it can work, nothing else. PC100 and 133 are backwards compatible with PC66, as long as the rest of the specs are good.

What definitely works: 16MB DIMMs with 8 chips (16Mb each) and 32MB DIMMs with 16 chips (16Mb each).

Some people report getting 64MB DIMMs with 64Mb chips working, but I've never had any success. What could work are huge 64MB DIMMs with 32 chips with 16Mb each. However they are rare.

matti157 wrote on 2021-05-29, 21:40:

CoffeeOne wrote on 2021-05-29, 17:04:

Get 2 double sided modules with 8 chips on each side, for 2 times 64MB = 128MB

Like https://www.ebay.it/itm/333966519804 ?

Do they have 8 chips on each side? Nope...

Also, the chips have fake labels on them, "tmmc" is not a DRAM chip manufacturer. These were probably PC100/133 reject chips not capable of running at spec, so re-labeled and sold to run at slower speeds. Avoid. Stick to known chip manufacturers (Samsung, Hyundai/Hynix, Micron/Infineon, Toshiba, Nanya etc) and preferably choose DIMMs made by the same manufacturers, or at least by reputable DIMM vendors (brands like Kingston)

Tbh, I'd go with two easily sourced 32MB DIMMs with 16 chips each, giving you 64MB total.

Basically this, https://www.oreilly.com/library/view/pc-hardw … ch05s04s02.html but it's way down the order there only supporting 16Mbit.

Here's one of the huge buggers, 64MB 16Mbit 32 chip SDRAM above a 32MB 16Mbit 16 chip...

Thanks everyone for the replies, I love this forum

CoffeeOne wrote on 2021-05-29, 22:44:

No. As I wrote, likelyhood is higher that it works, when you find double sided modules (with 16 chips on each module). […]
Show full quote

No.
As I wrote, likelyhood is higher that it works, when you find double sided modules (with 16 chips on each module).

EDIT:
Is the working module (the 32MB one) double sided? Double sided means that is has chips on both sides.

If it is single sided, then you should try to find double sided 64MB sticks in my opinion.
But when the working module is already a double sided one, then maybe just try to find a similar one, and just have 64MB.

I had misinterpreted the answer, I only now discovered the super sticks of 64, made from 2 sticks of 32 "stacked", I'm sorry

dionb wrote on 2021-05-29, 23:22:

This technical manual? http://ps-2.kev009.com/pccbbs/commercial_desk … op/d4as3tim.pdf […]
Show full quote

This technical manual?
http://ps-2.kev009.com/pccbbs/commercial_desk … op/d4as3tim.pdf

Not impressed by that manual. It seems exhaustive, up to descriptions of every pin on every connector, but leaves out a lot regarding memory.

First up- one thing included in the tables for cache, but not mentioned in the memory bit: the i430VX chipset can only cache 64MB. Everything over that will be uncached, so 128MB will be slower than 64MB, unless you actually fully use 64MB and start thrashing to virtual memory. If you want to run period-correct games that perform well on a P166MMX, you really don't need more than 64MB.

Then regarding the modules: the i430VX was the first SDRAM-supporting chipset and in retrospect it is very choosy about its RAM. IBM could/should have given exact specs required. "PC66" is the least relevant part: the speed rating of a DIMM indicates how fast it can work, nothing else. PC100 and 133 are backwards compatible with PC66, as long as the rest of the specs are good.

What definitely works: 16MB DIMMs with 8 chips (16Mb each) and 32MB DIMMs with 16 chips (16Mb each).

Some people report getting 64MB DIMMs with 64Mb chips working, but I've never had any success. What could work are huge 64MB DIMMs with 32 chips with 16Mb each. However they are rare.

matti157 wrote on 2021-05-29, 21:40:

CoffeeOne wrote on 2021-05-29, 17:04:

Get 2 double sided modules with 8 chips on each side, for 2 times 64MB = 128MB

Like https://www.ebay.it/itm/333966519804 ?

Do they have 8 chips on each side? Nope...

Also, the chips have fake labels on them, "tmmc" is not a DRAM chip manufacturer. These were probably PC100/133 reject chips not capable of running at spec, so re-labeled and sold to run at slower speeds. Avoid. Stick to known chip manufacturers (Samsung, Hyundai/Hynix, Micron/Infineon, Toshiba, Nanya etc) and preferably choose DIMMs made by the same manufacturers, or at least by reputable DIMM vendors (brands like Kingston)

Tbh, I'd go with two easily sourced 32MB DIMMs with 16 chips each, giving you 64MB total.

The manual is that! All very clear now, you have given me some very interesting information

I replaced the 166 with the 233, so it doesn't change anything I guess, because it’s a chipset limit

BitWrangler wrote on 2021-05-30, 00:19:

Here's one of the huge buggers, 64MB 16Mbit 32 chip SDRAM above a 32MB 16Mbit 16 chip...

Never seen ram like this, they look like server ECC