PowerMac 7600 3.3v ram

[thegeforce]

Hey all, recently got a powermac 7600 and want to get some extra ram for it. Does this machine support 3.3v EDO/FPM DIMMS? or can 3.3v dimms be used regardless of the voltage difference? Am asking becuase i can get 128 and 256mb 3.3v EDO or FPM DIMMS for roughly $35AUD on ebay instead of $50 for a 64mb stick for $100 for a 128mb stick thats tested to work with these powermac & clones.

thanks.

 

[uridium]

I just did some 3.3v dimms from A1 computers (see post). They may also have what you're looking for

I didn't know the 7600 was a 3.3v oddball. TIL. Hope you get it working! Post some photo's when you do so others can search for the same DIMM's etc.

Kind Regards.

 

[thegeforce]

I just did some 3.3v dimms from A1 computers (see post). They may also have what you're looking for

I didn't know the 7600 was a 3.3v oddball. TIL. Hope you get it working! Post some photo's when you do so others can search for the same DIMM's etc.

Kind Regards.

ive read it supports 5v ram, but i cant find any difinitive info that says that 3.3v ram wont work. (also thanks for reminding me of A1 Computers, i buy hard drives from him all the time lol)

 

[Powerbase]

I'm pretty sure it needs 5V dimms, not 3.3v.

 

[uridium]

*Nod* It was my first purchase from A1. Orbii on IRC told me to try him. PITA++ payment options and his shipping calculations are completely whack with the whole "this is the excessive shipping amount" ..then you get a refund of the difference. ah well! At least it arrived within a week which was great.

 

[thegeforce]

*Nod* It was my first purchase from A1. Orbii on IRC told me to try him. PITA++ payment options and his shipping calculations are completely whack with the whole "this is the excessive shipping amount" ..then you get a refund of the difference. ah well! At least it arrived within a week which was great.

yeah it is a bit odd how he does payment but it works so *shrug*. used to hang out at the shop somewhat often in 2019 before he went fully online.

h does have 3 168pin EDO DIMM's up on the site, those are 3.3v sticks unfortunetly.

 

[uridium]

Yeah. I don't want to bag him out, but I purchased 6 dimms that were all "3.3v", 3 worked (jackpot) and three were actually 5v when I pulled up the datasheet on the IC's. I'm not complaining though because I deliberately hedged my bets 2-ways with this project and will probably use the others in different system. Still brilliant that he exists.

 

[thegeforce]

Yeah. I don't want to bag him out, but I purchased 6 dimms that were all "3.3v", 3 worked (jackpot) and three were actually 5v when I pulled up the datasheet on the IC's. I'm not complaining though because I deliberately hedged my bets 2-ways with this project and will probably use the others in different system. Still brilliant that he exists.

hmm, might roll the dice so to speak, since its only $15 a stick.

oh definetly, hes the only local shop that sells this old stuff and has a consistent supply of various parts (unlike ebay haha)

 

[Franklinstein]

Memory was such a pain in this era. 3.3V or 5V? Buffered or unbuffered? Single or dual bank? EDO or FPM? And that's not even getting into the RISC workstation and server weirdness or application-specific laptop form factors.

I'm glad these days it's pretty much all a minor variation of the same standard (except in serverland which still has plenty of weirdness).

 

[Coloruser]

Per hardware developer notes, Catalyst, TNT, Tsunami etc. only support 5v EDO or FPM. 3.3v has a different keying - it will not physically fit in a 5v socket. The Tanzania (Motorola Starmax or Apple 4400) are the only 3.3v EDO compatible machines afaik.

 

[CC_333]

Which is easier to find?

It seems like most PCs of the time used 3.3V RAM (unless I'm mistaken), which, naturally, makes that the easier of the two types to find.

I have a PowerTower Pro/225 I wouldn't mind maxing out someday.

c

 

[derFunkenstein]

Per hardware developer notes, Catalyst, TNT, Tsunami etc. only support 5v EDO or FPM. 3.3v has a different keying - it will not physically fit in a 5v socket. The Tanzania (Motorola Starmax or Apple 4400) are the only 3.3v EDO compatible machines afaik.

I learned this the hard way in my first retro Mac purchase, a Power Macintosh 7300 with a G3 400 upgrade card. It came with 64 MB of memory and I stupidly bought a bunch of uber-cheap PC100 168-pin DIMMs. That was back when the price of pre-G3 systems was through the floor in like 2007-08. While the pin arrangement appears to be identical, the notches are not in the same places.

 

[Franklinstein]

Which is easier to find?

It seems like most PCs of the time used 3.3V RAM (unless I'm mistaken), which, naturally, makes that the easier of the two types to find.

I have a PowerTower Pro/225 I wouldn't mind maxing out someday.

Honestly, I find that most PCs of that era were either 72-pin SIMM or SDRAM (PC66) compatible. I rarely come across 3.3v EDO. It feels like consumer PCs kinda skipped the EDO/FPM DIMMs and went straight to SDRAM, though I'm sure there are plenty of Super 7 boards with universal RAM slots that would accept either the 3.3v unbuffered EDO/FPM or SDRAM.

Basically any G2 Mac that's not based on a Tanzania/II board uses 5v buffered EDO/FPM DIMMs. G1 machines were all 72-pin SIMMs, G3s and later were all SDRAM (though iMacs would use laptop SDRAM SODIMMs in some models). PowerBooks were unique and used special RAM cards until the PB G3 WS started using standard SDRAM SODIMMs (the only prior exception being the PB2400 which used standard EDO SODIMMs).

 

[cgp]

FWIW, at the end of last year, I upgraded my PM7600 with 4 sticks of this stuff: https://www.ebay.com/itm/155726506302

 

[trs]

[…] any G2 Mac […]

[…] G1 machines […]

I beg your pardon? When did “G1” and “G2” enter the vernacular? It must be recently because it certainly wasn’t something anyone ever said either when these machines were still relevant, nor were these terms used in the G3-G4-G5 era. Or the Intel eta, for that matter.

I could guess what you mean from context clues, but I don’t want to complicate things further. I’d rather hear your explanation first.

 

[derFunkenstein]

"G2" was in use in 1998: https://ieeexplore.ieee.org/document/743188

It's also here: https://www.mackido.com/Hardware/G2.html

I doubt it's been used widely, but I saw a video somewhere saying Jobs even said it. I know, I know, I should cite my sources. I'll work on that.

 

[Coloruser]

I worked with Motorola/Ireland during the Clone Era and they also used the term G1 and G2 on their slides - most likely to separate it easier from the upcoming G3. The general public did not make use of it and in any kind of adverts, the G1 or G2 term was not used - afaik.

 

[thegeforce]

Hey everyone, thanks for the info, will kep a lookout for 5V DIMMS on ebay.

 

[envirogeek]

Hey everyone, thanks for the info, will kep a lookout for 5V DIMMS on ebay.

Were you successful tracking any done? What sizes are you looking for?

I have at least one spare 64 GB Kingston stick, and I have 8 OWC 128s in a system, which is way more than I need.