Memory mystery

antilles

Wonder if someone can help me -

My laptop has in it 2 sticks of 256Mb SODIMM PC3200 DDR 400Mhz.

I want to boost the memory and got my hands on a stick of 512Mb SODIMM PC2700 DDR 333Mhz.

Can I mix the different speeds of memory in the laptop? I tried installing a 256 and the new 512 stick (it only has 2 slots) but the laptop never shows more than 512Mb of memory (according to the MB manual the maximum is 1GB). The 512 stick is definitely compatible with the laptop as it runs fine with it installed. But no matter what combination / slots I use I can never get more than 512Mb to show.

I'm assuming this is because the memory speeds are different? Could the laptop be ignoring the 256Mb stick because it's a higher speed?

isofa

It could be that the laptop requires the faster DDR 400 RAM, so can't access the slower DDR 333 chips. BUt that doesn't match your experience.

What make and model is the laptop, we can check at https://www.crucial.com/uk

antilles

It's a Mitac 8555 (rebadged by Novatech)

wakandem

try getting into the bois and changing the memory speed to 333-166 . It should see both of them and run at the slower speed

isofa

Can't find that model on the Crucial website

wakandem's bios tweak will probably sort you out though!

fwor

I've had exactly the same problem - not on a laptop, but a Shuttle SFF. It seems that some motherboards simply can't handle a mix of memory speeds.

One other thing which I have also seen (again on a desktop PC) was that the BIOS had to be updated to be able to address the theoretical max for the motherboard.

antilles

Thanks for the replies everyone.

isofa - Yeah it's not on the Crucial website, although I ran their configurator and the Crucial techies seem to think it should take DDR 333. This must be correct because it will handle either 333 or 400.

wakandem - Looked in the BIOS - it's fairly limited, doesn't seem to be any way to tweak memory. It appears the laptop has no problem running both the 512 (333) and the 256 (400) at the same time, just that it seems to ignore the 256

fwor - yeah, beginning to wonder if it's either a motherboard limitation or like you say, the BIOS can't handle more than 512.... but the MB manual does specify a max of 1Gb. I'll go and see if I can update the BIOS and see what happens - worth a try!

ormus

once had a PC with 1gb ram in it and the mobo bios could only see 512mb.
it ran ok though and it was using the whole 1gb. just wierd.

when you mix ram speeds the PC normally works ok, it just runs the ram at the slowest speed of the mix.
lappys are always wierd though.

wakandem

as stated, some motherboards are just fussy. In the 1st instance you need to see both sticks in the bios otherwise windows wont see them.
dont flash/update the bios unless you have tried 2 sticks of the same spec,

antilles

I got a BIOS update from the Mitac website which is allegedly for my laptop, however there's no supporting documentation with it, just the flashing utility and the BIN file. So I think I'll give that a miss in the absence of hard evidence that it's even the correct one!

Will get hold of some more memory and try that - if not then back to the drawing board.

Bl**dy laptops!