[mtgx]

Most Rapsberry Pi's have 256 MB of RAM. Only the initial batch had 128 MB I think.

[darkstalker]

The RAM on the RPi is shared with the GPU, so you have less than 256 MB available

[seabee]

Model A is specced for 128 MB, but that's not available yet.

[vardump]

Model A was later respecced to have 256MB as well, just like Model B.