[Pi 1536] Upgrade RAM

[Tomahawk]

Hi everyone! My sister has this laptop and it is with 1GB (2x512MB) Ram DDR2 533.
I want to upgrade only the ram but I am not sure which type will work.

At first I though that it will be better to buy 2x1GB DDR2 533, but I found this post: http://forum.ts.fujitsu.com/forum/viewtopic.php?f=90&t=28689
In the 10th answer the user says that he work with 2.5GB Ram and the one is 800Mhz.

I was affraid of BSOD because of the memory different frequency but that post gave me hope
Kingston and Corsair DDR2 800Mhz are the cheapest and I would like to buy one 2GB Dimm and fit it with the one 512MB.

What do you think? 2GB 800Mhz Dimm will work with the factory bios (I don't want to change it)??

[sabrex]

 Up to 2GB DDR2 in 2 SO-DIMM slots
i was not aware it will work beyond 2GB as this is the MAX
the forum link guides you to altering the bios in order for this to work

[Tomahawk]

 Up to 2GB DDR2 in 2 SO-DIMM slots
i was not aware it will work beyond 2GB as this is the MAX
the forum link guides you to altering the bios in order for this to work

"Nuno" in the 10th answer doesn't have another bios and it works...
That's why I am confused!

[Z4CHARiAS]

well, afaik, original BIOS support up to 4gb of ram dd2 up to 667mhz, correct me if im wrong.
so search ram between those parameters.
kudos