Your PS3 has a hypervisor that limits your use of your power machine. And when running on Linux, it makes you use swap memory (uses HDD for memory), which is very low but more specifically 26MBs.
This presumes your flash devices have been previously formated for you and contain a partition table. WARNING! This procedure will destroy all data on the SD card and the USB key!
Open a terminal. Enter the following commands:
[type in your root password]
/sbin/swapon -p 1 /dev/sdd1
/sbin/swapon -p 1 /dev/sdf1
You are now running with swap space evenly distributed between the two flash devices. If you like it we continue the procedure: edit the following file:
remove the line that contains the word "swap" in it. Add these two lines instead:
/dev/sdd1 swap swap pri=1 0 0
/dev/sdf1 swap swap pri=1 0 0
Thats all. You can probably use a memory stick or SD card, but you would have to figure out what to change.