is pc100 memory compatible with pc133 ??

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code_wrong

Hi, a friend has a Packard Bell Club 50 ....
When I search for a memory upgrade at crucial.com The results in include
both pc100 and pc133. This surprised me as i did not think the two would be
compatible ... ....

The system has 64 MB installed .. but I am not sure if it is pc100 or pc133
.... I f I buy pc133 and it has pc100 will the two memory sticks play nice??

cheers
cw
 
If the type of memory is correct, usually adding faster memory to a computer
than what it needs isn't a problem. Some computers have been known to get
picky, but it usually works.

Basically what happens is that the motherboard is programmed to wait a
certain number of milliseconds for the memory to be ready. The memory has to
be fast enough to be ready in that time frame. If it's ready early, that's
usually no problem. In fact, I would venture to guess that even if you put
pc100 memory in, it will be ready before the motherboard comes back to check
on it. There is probably a small (very, very small) overlap built in for
safety.

The reason I say usually is, as mentioned above, there are some motherboards
that just don't like it for some reason. I've also seen problems with two
different brands of memory in the same motherboard, although if they were
placed in the motherboard separately they both worked fine. I don't know
what causes these sort of problems. Fortunately, they don't occur often.
 
Hi, a friend has a Packard Bell Club 50 ....
When I search for a memory upgrade at crucial.com The results in
include both pc100 and pc133. This surprised me as i did not think the
two would be compatible ... ....

The system has 64 MB installed .. but I am not sure if it is pc100 or
pc133 ... I f I buy pc133 and it has pc100 will the two memory sticks
play nice??

cheers
cw
Click to expand...
Crucial is pretty smart about this kind of thing. It is their business so
if you gave them correct information, they will stand behind it.
 
PC100 memory will work with a 133 Mhz bus, but PC133 memory will not work with a 100 Mhz bus. If you have a 100 Mhz bus you can mix PC100 and PC133 memory. It is common to have problems with memory chips that are higher density than your motherboard chipset is designed for. If you install a 256 MB DIMM with 4 chips it might not work or recognize only 128 MB. It would be more likely that a 8 chip DIMM will work.
 
PC100 memory will work with a 133 Mhz bus, but PC133 memory will not work
with a 100 Mhz bus.
Click to expand...

Uhh? Not really true, maybe you were thinking of some
specific situation? I'd think it more common to assume the
opposite, that PC133 would work with the 100MHz bus, unless
we're also considering asynchronous buses, in which case
some did plus 33 AND minus 33 from FSB speed.
If you have a 100 Mhz bus you can mix PC100 and PC133
memory. It is common to have problems with memory chips that are higher
density than your motherboard chipset is designed for. If you install a 256 MB
DIMM with 4 chips it might not work or recognize only 128 MB. It would be more
likely that a 8 chip DIMM will work.
Click to expand...

True, but then it's up to the user to determine if that's a
"problem". If the board can only use 128MB per slot and
user installs 256MB of PC133, which is working ok as 128MB
and that costs nearly the same as 128MB of PC100, there
might be no real incentive to do anything more.
 
Sorry, I had it backwards, PC133 will work on a 100 Mhz bus, but PC100 in most cases will not work on a 133 Mhz bus. Good thing we have kony around to catch our mistakes.
 
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