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Amilo Si1848 RAM limit

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Amilo Si1848 RAM limit

Postby leopardsanderson » Wed Jun 11, 2008 3:40 pm

Hello everybody.
I have a Amilo Si1848 with 1.66 GHz Core2Duo, and 1Gb RAM made of 2x512MB slots as usual.
I would like to upgrade it. First of all I have to figure out where the second slot is but probably under the keyboard which I'll open up soon to check (and then post since no one yet posted this info for the si1848).

I'm wondering if anybody knows something about the RAM amount limit for this and similar laptops.
In a official FSC forum http://forum.fujitsu-siemens.com/forum/viewtopic.php?f=90&t=28689 they say that upgrading to 4 GB (2 x 2Gb slots) can't boot up at least for another amilo!! Since the intel chipset supports it I suppose it's the BIOS that doesn't support it. If upgrading to 4Gb is not possible do you think that unbalancing the slots (i.e: 1x 512MB and 1x 2Gb) will drop down performances?
These things are bugging me pretty much... Freakin'hard to find infos, to find the second slot, and impossible to upgrade to 4GB!!! I know they say that XP doesn't support more than 3-3.5 Gb (fixed anyway by the SP2 as I well remember) but Jesus!!!
And you know what? The support told me that I shouldn't go higher than 2x512 Mb configuration because is the only one supported!
Bah...
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Postby hikaru » Wed Jun 11, 2008 4:04 pm

The chipset supports 4GB.
If the bios does? Nobody knows until someone (you ;-) ) tried.

4GB is not supported by any 32bit OS neither WinXP, nor Vista nor Linux.
But at least Vista 32bit seems to boot with 4GB and recognises them (with SP1). But it can't use the whole capacity.

Notebooks with shared memory (like mine) have problems when loading graphics drivers in 32bit XP and Linux if 4GB RAM is installed (black screen). Vista works with it.
I don't know if you will have the same problem since your graphics isn't on board.

XP SP2 does not fix the 3.xGB-bug! Vista SP1 at least makes it recognise but not use 4GB. I don't know if XP SP3 has a similar effect.

A mixed-RAM-configuration will run as fast as the slowest module. Additionally it will most likely not run in dual channel. So if you don't need the extra capacity, avoid running a mix.
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Postby leopardsanderson » Wed Jun 11, 2008 7:12 pm

ok thanks!

Uhm, but I still miss the reason why these OSs can't use the whole address space... I thought: 2^32=4GB so why they don't... misterious... :shock:
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Postby hikaru » Wed Jun 11, 2008 7:49 pm

Some months ago this question came into my mind too. :)

It has to do with the graphics memory and the AGP aperature size.
They use the same address range as the RAM and therefore their size has to be subtracted from size of the adressible RAM.
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