I discovered a bunch of RAM in my junk box of old computer parts and realised there could be some useful stuff in there. In this old Celeron 433 PC I have here, it only detects half of the 256MB chip, so I'm guessing the chips are double sided.

Before I go selling it, I want to know which Macs could use double sided SD-RAM. So whoever buys it isn't in the crappy situation of being sold RAM that only half works in their machine (a place I've been and it blows).

Yes it does work. I have installed it G3 imacs and G3 powermacs. It even worked in a G4 cube, but don't quote me as i can't remember if it was double sided.

The SDRAM in my iMac/400, beige G3s and G4/400 is double sided, and works ok.

However, if it's anything like 72 pin simms and their issues with doubleness, it's double <i>banked</i> that may be an issue, not double sided. Some macs didn't handle double banked ram, regardless of the number of chips on a side - you could get double sided single banked, or single sided double banked, or other combinations - and except for physical fit issues, double banked was what defined how much RAM was seen.

Dana

Just to clarify, I don't think any G3 machines run PC133 at 133, it will only run them at 100 which is fair enough.

I know some highend G4's and certainly QuickSilvers run PC133. Use MacTracker and find out what it can take!

both sawtooth and yikes g4s use pc133 double sided, but sawtooths such as mine only run it at 100.

there are only a limited number of early g4s (if any) that won't use double sided pc133 ram in some way.

how many MBs are your ram chips.

Ahh, double sided 168-pins! Some people call this stuff 'server' or 'HP' RAM.

Apple started using 168-pin DIMMs with the introduction of the G3/266, requiring PC66. The G3 blue-and-whites used PC100.

All G4s used 168-pin up until the QuickSilvers (QS and QS2002). With the MDD, they switched to PC2100 (266 MHz) DDR. G4's used PC100 in the first-generation G4's, and PC133 in the next gen.

The memory controller used in the grey G3's, the B&W G3's, and the G4/400-PCI was a bit of an odd biscuit, in that they had a limit of 256 MB per socket, and expected double sided sticks -- if the stick used double-banking on one side, only half the stick would be recognised. And even with that, there wasn't a 100% chance that a particular DIMM would work in a G3, because of Apple's rigorous timing demands.

Whilst the 256MB sticks can be used in any Mac that takes PCxxx, the double-sided ones are of most use to someone wanting to eke out some extra life from an old G3.

In the FWIW Dept: Umart still sells 256 MB PC133 double-sided for $66 a stick.


Brains

I've no doubt that 256MB sticks can be used, however, being double sided/double density may cause the machine to only recognise half of the stick, not the full 256MB. Is it possible to know beforehand which machines will recoginise the full amount and which machines can't?

Not readily, no. It could be that your old Celery is just way too old, and only works with single-sided stuff (I had an old Compaq Celeron-based machine with that issue).


B.

I can get ram like this for $41 a stick.

Either 222 or 333 speed (yes 222 is what apple 'requires', but I can tell you that despite this, 333 also works in most (possibly all) apple machines that take pc100 or pc133, i.e. first and second gen g4s).

Yes, it's generic brand, but I've never had a problem with it either in a sawtooth or a couple of dozen different types of PCs.

I am also under the impression that it can be had for $30-$40 second hand from forums such as these.

re price: Yup, 'twas only using the Umart as an example, and I picked up a pair last month for $20.

re speed: The RAM-makers only really bothered with CAS/RAS time-testing back in the PC66/PC100 days, when the higher-spec stuff could demand a premium price ... as the fabbing technology improved, by the time 128 & 256 MB PC133 sticks became the norm the timing had improved so they were pretty much all 222. That said, it would depend more on the age of the RAM as to what timing it is ... early 128's & 256's will fail in some Macs, I know, I've got some 128's here in a box that work fine in an old P3 I have, but inside either my grey G3 or my G4/500DP they either generate a crash-chime on POST or are not recognised at all.

For the 256 133's that decryption has, the chances of them not working in a Mac border on the infinitesmal, but the chace does exist.


B.

Yep. Cool. So does this mean decryption's targets are:
- 'dozers
- late model b&w g3s (i.e. >66mhz)
- any g4s except the last model (is it mdd or da i always forget)

... any G4 up to the last QuickSilver 2002, so yes, the MDD's are off the list.