cskamacska wrote:

Hi folks! […]
Show full quote

Hi folks!

I happen to have 4 pices of 64MB 50ns(or 60ns - I need to double check) 72 pin SIMM FPM modules with parity check. I thought they could come in handy with ram upgades, 256MB of RAM is more than enough for most retro needs, but I don't know what kind of motherboards support such high density modules. Also would there be a big performance impact when "downgrading" from standard EDO RAM? (32MB 60ns is the best EDO module I could find, larger modules a practically non existent for me) 4x32MB is enough for Win 98, but no memory is enough for certain programs, not to mention dual booted Win XP(I always wanted a haxorord DOS7/Win98/WinXP multi boot system on a FAT32 partition) probably needs 256, but then again it is just FPM RAM and that probably doesnt help the overall system speed. 😒

Could I upgrade a Gigabyte GA-586DX dual Pentium mobo with these sticks? Or could there be a Socket 4 motherboard that can be fitted with these modules(I have a Socket 4 Pentium Overdrive laying around and wanted to put in a working machine for a long time now)?

Thank you for your advice in advance!

Hello and welcome to the forum (although you already joined in 2008 hehe 😜 )
The biggest issue on P1 era motherboards is the maximum cacheable area. Most motherboards of that era won't cache memory above 64MB.
If you do install more memory, your system will run slower with low memory usage. The only reason to install over 64MB of ram on a system that won't cache the ram above it will be if you otherwise get a lot of harddisk trashing from using virtual memory.

iirc the socket 4's could cache 128Mb ram (correct me if I'm wrong).

I suppose changing from EDO to FPM won't matter that much, but it will run slower ofcourse, unless the extra memory will prevent harddrive trashing.

The 430HX could cache up to 512 MB if Tag RAM cache was present. Motherboards based on this chipset should be able to do 4x64 MB. The List of Intel chipsets is helpful in estimating motherboard's capabilities.

The point with the HX is, that you need 8 SIMM Slots for 512 MB. (with the 64 MB SIMMs)
The well known ASUS board has 4 and the GA586DX too. So you will have 256 MB max.
The GA586HX has 6 -> 384 MB
The Tyan Dual Board has 8 but (at least my) seems to be very sticky for memory modules between second CPU and RAM.
This was quite annoying to find, since memtest86 just checks from the first CPU to RAM and this was always fine.
If someone knows a memtest86 that also checks second cpu to RAM, I am interested 😀.

I think there are 128mb SIMMs as well. I thought those worked on a lot of HX boards, do they not?

What did a 128MB SIMM cost in '96? 😁

swaaye wrote:

What did a 128MB SIMM cost in '96? 😁

I'd say a kidney or so...
worst part is, you need to use SIMM's in pairs 😁

Most motherboards have electrical limitations - they state, you shouldn't use modules with more than x chips. My favourite HX ASUS P/I-XP55T2P4 says not to use over 24 chips - 16 chips is standard maximum, 18 - parity maximum, 24 - ECC maximum. Whether it will work with 128 MB depends on chipset and memory organization - but I never was sure whether I'm counting it correctly. http://www.intel.com/design/chipsets/datashts/290551.htm

GL1zdA wrote:

Most motherboards have electrical limitations - they state, you shouldn't use modules with more than x chips. My favourite HX ASUS P/I-XP55T2P4 says not to use over 24 chips - 16 chips is standard maximum, 18 - parity maximum, 24 - ECC maximum. Whether it will work with 128 MB depends on chipset and memory organization - but I never was sure whether I'm counting it correctly. http://www.intel.com/design/chipsets/datashts/290551.htm

Owning 10 64MB FPM SIMM's with more then 24 chips, I've actually found no board that can take these modules, except for some very obscure HP server boards 🙁

Wow, thank you for the help guys! 😎
Im a bit embarrassed as I used to browse Chris Chare's brilliant specification database http://mysite.verizon.net/pchardwarelinks/, including the motherboard(old Pentium nowadays) chipsets chart http://mysite.verizon.net/pchardwarelinks/chi … ets_pentium.htm.
I also used my common sense at last and downloaded the manual for GA-586DX and it states the maximum memory is 512MB, with a limit of 128MB per module, and the onboard 512KB L2 cache can cache the entire supported amount.
I also found that the i430LX based Socket 4 boards have 16/32MB module limit, and even with lotsa 32MB sticks the max cached amount would be about 64MB. So no XP for me on the Overdrive. 😵
128MB 50ns EDO RAM would be better, but is impossible to find, I am glad to own even these 64MB modules.

Tetrium wrote:

Owning 10 64MB FPM SIMM's with more then 24 chips, I've actually found no board that can take these modules, except for some very obscure HP server boards 🙁

Yeah, I bought them to - they're PA-RISC modules, 64-bit wide, so they definitely won't work on a PC (I guess, these have all connectors unique, unlike PC SIMMs, where connectors on both sides of the module are doubled). And unfortunately my only PA-RISC is to old to use them (Apollo 715/50).

Two years back I saw 128mb SIMMs on ebay selling for peanuts. I ended up going for some very nice compaq 64mb FPM SIMMs instead since I didn't have any systems capable of handling higher densities. Looking back perhaps I should have bought the 128mb SIMMs too.

GL1zdA wrote:

Tetrium wrote:

Owning 10 64MB FPM SIMM's with more then 24 chips, I've actually found no board that can take these modules, except for some very obscure HP server boards 🙁

Yeah, I bought them to - they're PA-RISC modules, 64-bit wide, so they definitely won't work on a PC (I guess, these have all connectors unique, unlike PC SIMMs, where connectors on both sides of the module are doubled). And unfortunately my only PA-RISC is to old to use them (Apollo 715/50).

I did try them out on a couple motherboards and it booted in every single case, even on a socket 3 board it counted all the way to 64mb for 1 SIMM.
When I tried on a SiS 5598 board with 2 of the modules I got BSoD until I put back the original memory.

Well, hope I didn't break anything!

I have several 128meg, 50ns EDO sticks NIB. PM me if interested.

Edit: sorry, what I have are DIMMs