It's no secret that the Dell Mini 9's maximum RAM size is 2GB. Dell purposely configured the Mini with a maximum of 1GB of RAM so that they could ship it with Windows XP.
In order for an OEM to buy a Windows XP license from Microsoft, their computer's specifications have to be below a predetermined minimum. If the Mini shipped with 2GB of RAM it would have been above the minimum and customers would be forced to buy Vista.
I can understand how this is beneficial to Windows users. I would prefer to run Windows XP over Vista on my Mini. Windows XP runs faster, takes up much less disc space, and is more memory and power efficient.
This memory limit doesn't make sense for Linux Users. We were only offered an upgrade to a maximum of 1GB so the Windows users could get their Mini's with XP. I'm not angry because it is an easy upgrade that anyone can do. It's also much cheaper for you to upgrade the RAM yourself.
WARNING: For users still running Dell's custom Mini OS based on Ubuntu 8.04, Dell modified the kernel and limited the maximum amount of RAM that Mini OS will see/use. If you want to upgrade your RAM over 1GB you will have to recompile your kernel or install a non-Dell version of Ubuntu. You can download Ubuntu
here and use Ubuntu Mini's
install guides to help you get everything up and running.
1. What You'll Need

1- Unplug your Mini 9
2- Phillips Head Screw Driver
3-
Groundind/Static Bracelet
4- 200pin DDR2800 (PC6400) RAM
5- Remember to read the instructions first.
2. Remove The Battery

Slide the battery locks outward and pull the battery out.
You
do not want electrical current running through your Mini while upgrading.
3. Unscrew and Remove the Back Plate

Remove the two philips head (crosshead) screws highlighted in the
red boxes.
4. Remove The Old RAM

Gently push the silver headed white tabs on the side of the RAM DIMM outward to release the RAM. This should cause it to slightly angle outward.

Gently pull the RAM out from the DIMM slot. It should release easily.
5. Install the New RAM

Line up the notch on the RAM to the notch in the DIMM slot (where is says REV).
Push the RAM into place at a 15 degree angle.
Once RAM is correctly aligned and fully inserted gently press down to lock it into place.
6. Replace The Back Cover & Screws
7. Check Your RAM
In a termianal type:
head /proc/meminfo