pc133 sodimm backwards compatible to pc100? And other questions ...

[billandopus]

I just picked up an IBM a22e celeron 800 laptop off lease for basic school use.

It has 128mb of pc100 memory, I think.

AFAIK it's got a max installed 256mb according to the info i've gotten.

So, i've got a few questions.

1 - i've heard that pc133 sodimms are NOT backwards compat with pc100 sodimms? Is that correct? Besides that - is there any particular reason why I would bother putting in the pc133 anyways if I had the chance?

2 - Max memory - is there any way to possibly increase the max memory? Like through the bios either to trick it or to possibly flash it? I don't think i've heard of flashing bios enabling more memory to be used but i'm checking on this one because i'd like to put more than 256mb (what the hey!).

Thanks a bunch.

 

[Jeff7]

It isn't so much the PC133 part that it might have trouble with, but the fact that most PC133 is high-density. I'm not entirely clear on what this means - I think it has to do with the amount of memory per chip.

Only way to increase the max memory might be with a BIOS update, if one is available. And if there isn't one, I doubt they'll be doing any updates for a Celeron 800 laptop.

 

[billandopus]

Thanks for the info.

Can anyone definitively say whether or not you can use pc133 sdram sodimm for a laptop rated (I believe) for pc100?

Thanks.

 

[UltraWide]

Just like Jeff7 said.

You need to check the density of the memory before you buy it.

Back in the days notebooks sometimes were rated below their max capacity because 512MB soDIMMs were non-existent and not qualified, but now they are very common and cheap. You might be lucky to just pop one in and find out it works as long as the chipset can address the RAM.

 

[jschuk]

Some PC133 modules may work and other will not. Just today, I put in a 256MB PC133 chip into a Toshiba 1755 (which isn't listed in the specifications). The first two modules I tried didn't work, but the third did. The first two contained 4 chips per side and the third contained 8 chips per side. The laptop comes with 64MB built-in and has one slot that is rated for "up to 128MB", but we put 256MB in them just the same.

 

[billandopus]

Again, thanks.

I've been doing my research and i've found some conflicting info. One link says this laptop has a 256mb RAM limit while another link says max 512mb.

*edit* more and more research finds that the max memory is 512mb pc100 in a 2x256mb config but of course.

Guess I will have to find out whether I could bring in the laptop and see if the memory will work or not right off the bat.

Mystery solved.

 

[DaFinn]

I've had an a22e (currently at my parents), and I can say it's VERY picky with memory!!! I tried several modules, but it would only accept
original IBM replacements.

Go to Kingston and use their memory selector to find right memory for it.

You might get lucky, but I'd only buy from a place where you can return it if it doesn't fit. Changes are nothing but IBM certified memory will work...

 

[billandopus]

Thanks for the heads up DaFinn. I'll do just that. Unfortunately, i'm North of the border so I don't have easy access to Kingston products via their website but i'll check it out. I'm doing okay with 128mb at the moment but I have plans to install XP ... maybe. We'll see.

 

[billandopus]

There's a bit of confusion but I figured it out.

The Celeron model of this laptop maxes at 256mb and the p3 model maxes at 512mb.