To find out what is the maximum system can support type the following command:

root@websvr:~# dmidecode -t 16

output

# dmidecode 2.11
SMBIOS 2.4 present.
Handle 0x0082, DMI type 16, 15 bytes
Physical Memory Array
 Location: System Board Or Motherboard
 Use: System Memory
 Error Correction Type: None
 Maximum Capacity: 1 TB
 Error Information Handle: Not Provided
 Number Of Devices: 64

As you can see the maximum memory capacity is 1 TB