Not the DDR memory controller on all PowerBook 12" models.
The DDR2 they refer to was confined to only the A1138 and A1139 final 15/17 PowerBooks, the DLSDs, and the jury is still out on whether those can be coaxed to accept a pair of 2GB DIMMs.
I don’t know what is the truth. I read that in several forums and YT channel, but never seen it. For me, 2GB was not enough either. Plus +250 MB are really very few here. 1.25 is enough to listen to music. Reason 4 and Ableton 7-8 (make music) required the G5 processor with more ram than 2GB. The PB 12” was not invented for this.
@weckart 2st black and red dragons are very popular here with a headphone like the ATH-M50X. This is a complex thing for that matter. It starts with a good RCA interconnect cable, through a good amplifier to the speaker. I really love the RED.