These are my notes on how to reduce memory consumption of debian on an HP t5135 thin client.

Add to modules blacklist:

blacklist snd_via82xx
blacklist snd_ac97_codec
blacklist snd_pcm
blacklist snd_timer
blacklist snd_mpu401_uart
blacklist snd_rawmidi
blacklist snd_seq_device
blacklist via82cxxx_audio
blacklist uart401
blacklist parport_pc
blacklist parport
blacklist pcspkr
blacklist soundcore
blacklist sound
blacklist via82cxxx_audio

Remove device mapper from init scripts:

update-rc.d -f libdevmapper1.02 remove

Edit /etc/default/acpid:

MODULES="processor button thermal"

For more info like this, check out dectop Debian tips