问Ubuntu 19.04只识别16 8GB内存中的8GB内存

EN

*-firmware                
       description: BIOS
       vendor: Insyde
       physical id: 0
       version: F.1E
       date: 12/25/2015
       size: 128KiB
       capacity: 6080KiB
       capabilities: pci upgrade shadowing cdboot bootselect edd int13floppynec int13floppytoshiba int13floppy360 int13floppy1200 int13floppy720 int13floppy2880 int9keyboard int10video acpi usb biosbootspecification uefi
  *-cache:0
       description: L1 cache
       physical id: 6
       slot: L1 Cache
       size: 32KiB
       capacity: 32KiB
       capabilities: synchronous internal write-back instruction
       configuration: level=1
  *-cache:1
       description: L2 cache
       physical id: 7
       slot: L2 Cache
       size: 256KiB
       capacity: 256KiB
       capabilities: synchronous internal write-back unified
       configuration: level=2
  *-cache:2
       description: L3 cache
       physical id: 8
       slot: L3 Cache
       size: 3MiB
       capacity: 3MiB
       capabilities: synchronous internal write-back unified
       configuration: level=3
  *-cache
       description: L1 cache
       physical id: 5
       slot: L1 Cache
       size: 32KiB
       capacity: 32KiB
       capabilities: synchronous internal write-back data
       configuration: level=1
  *-memory
       description: System Memory
       physical id: 25
       slot: System board or motherboard
       size: 8GiB
     *-bank:0
          description: SODIMM DDR Synchronous 1600 MHz (0,6 ns) [empty]
          product: 99U5428-063.A00LF
          vendor: Kingston
          physical id: 0
          serial: 19532259
          slot: Bottom - Slot 1 (left)
          clock: 1600MHz (0.6ns)
     *-bank:1
          description: SODIMM DDR3 Synchronous 1600 MHz (0,6 ns)
          product: M471B1G73EB0-YK0
          vendor: Samsung
          physical id: 1
          serial: 15262215
          slot: Bottom - Slot 2 (right)
          size: 8GiB
          width: 64 bits
          clock: 1600MHz (0.6ns)