According to http://www.theregister.co.uk/2010/08/25/arm_server_extensions/ http://www.theregister.co.uk/2010/08/25/arm_server_extension... there's an extension

According to http://www.theregister.co.uk/2010/08/25/arm_server_extensions/ http://www.theregister.co.uk/2010/08/25/arm_server_extension... there's an extension for 32-bit ARM processors that allows them to address 40-bit memory (1TB RAM). This before 64-bit processors (that should arrive in 2014) Btw I dont know if this option is available in Calxeda/HP solutions.