[geeks] Anyone know of good sources of 5V DIMMs?

[Geoffrey S. Mendelson]

On Sun, Jun 18, 2006 at 09:07:04AM -0400, nate at portents.com wrote:
> Hey folks, I'm going to be upgrading a bunch of old Macs for a non-profit
> company on the side, and use XPostFacto to get them running OS X. 

How old? In order to run OS X 10.2 or later, you need to have a G3 processor.

IMHO 10.0 and 10.1 are not worth running because they were to limited
in function and buggy, 10.2 is not because any recent programs that
are available were compiled under 10.3 and won't run on anything older.

Some things, such as the latest such as Mplayer binary, iLife'06, many
functions of Garage Band '05, won't work with a G3 processor anyway.

There are other problems for example, for example  Blue and White G3's and 
older (beige) G3's, early iMacs, etc won't support an IDE drive bigger than
12 gig for most brands and 20 for a few Maxtor ones. It's not a size
limitation, it's a hardware bug in the IDE controler chip and they
can't keep up with the drive.

10.3 and 10.4 work well with 256m of RAM. Note that many older machines
will not support more than 256m of RAM unless you turn of cache at boot
time (an X-PostFacto option). Once they are booted the cache is turned
on, so it is ok.

AFIK all of the machines that actually run OSX use 3.3 volt memory.
Be careful not to mix speeds and registered versus non registered memory.
B&W G3's and older will can not address more than 128m chips, so a 256m
DIMM/SODIMM must have 16 chips instead of 8 or it will only be a 128m.

Wallstreet powerbooks are a problem. The memory dealers all sell 66mHz SODIMMs
for them, but there are some models that require 100mHz. AFIK 100mHz ones
will work in all of them. There are size limitations for the bottom SODIMM
on Wallstreet, Lombadrd and Pismo powerbooks, and the CRT iMacs that
take SODIMMS.

I have Wallstreets that have large drives in them, one a 40, the other
a 60 gig. They work if make the boot partition less than 8,000 megabytes.
Yes, that's the correct number, 8 gig (8 * 1024 megabytes)  is too big.

There is a problem though, the orignal drive used half an ampere of 
DC (2.5 watts), the new ones use one ampere (5 watts), which changes the
heat patterns and battery useage.

Another thing to be careful of is batteries. I have several bad
Wallstreet batteries and laptops sidelined because a new battery costs
more than a used faster iBook.

If you do get an iMac, Pismo, Lombard  or desktop with USB ports, keep
in mind that the ports are only USB 1, and they are not bootable. VIA
chipset USB 2 cards don't work properly, they will work with keyboards
and mice, but not disk drives. If you do upgrade the USB ports, you will
need NEC chipset cards. (neither are the firewire ports, and some PCI
SCSI cards)
 
Geoff.
-- 
Geoffrey S. Mendelson, Jerusalem, Israel gsm at mendelson.com  N3OWJ/4X1GM
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