A RAID storage controller storage-device-assisted data update system includes a RAID storage controller device coupled to a host system and RAID storage devices in a “look aside” RAID storage controller device configuration. Based on command(s) from the RAID storage controller device, a first RAID primary data storage device may perform a first DMA operation to access first primary data stored on the host system, and write the first primary data to its first buffer subsystem. The first RAID primary data storage device may then perform a first XOR operation using the first primary data stored in its first buffer subsystem and second primary data stored in its first storage subsystem in order to produce first interim parity data, and write the first interim parity data to its second buffer subsystem. The first RAID primary data storage device may then update the second primary data with the first primary data.