http://www.w5j6stm77zs6652pgsij4awcjeel3eco7kvipheu6mtr623eyyehj4yd.onion/w/index.php?title=Cold_Boot_Attack_Defense
Unlike normal disk encryption systems, both encryption and decryption are performed by the disk controller which store the main encryption keys. This means encryption/decryption is not performed by software in the main CPU, along with the main encryption keys stored in DRAM.