The simplest way to check total installed RAM is using the sysctl command:

sysctl hw.physmem
sysctl hw.realmem

This will display physical memory in bytes. For human-readable output:

sysctl -h hw.physmem

The top utility provides real-time memory statistics:

top

Look for these key memory metrics in the header:

Mem: 1234M Active, 567M Inact, 890M Wired, 12M Cache
Swap: 1024M Total, 512M Used

For detailed hardware information including RAM slots and configuration:

dmidecode -t memory

Sample output showing DIMM details:

Handle 0x1000, DMI type 16, 23 bytes
Physical Memory Array
        Location: System Board Or Motherboard
        Maximum Capacity: 32 GB
        Number Of Devices: 4

Handle 0x1100, DMI type 17, 34 bytes
Memory Device
        Array Handle: 0x1000
        Size: 8192 MB
        Form Factor: DIMM
        Type: DDR4
        Speed: 2666 MHz

For virtualized environments or when dmidecode isn't available:

# Kernel memory map
vmstat -h

# Show memory hardware (requires root)
pciconf -lv | grep -i memory

# FreeBSD-specific memory reporting
grep memory /var/run/dmesg.boot

For automation purposes, extract just the numeric value in megabytes:

sysctl -n hw.physmem | awk '{print $1/1024/1024}'

Or for a complete JSON output suitable for monitoring systems:

{
  "total_memory_mb": $(sysctl -n hw.physmem | awk '{print $1/1024/1024}'),
  "free_memory_mb": $(sysctl -n vm.stats.vm.v_free_count | awk '{print $1*4}')
}

---

The simplest way to check RAM on FreeBSD is using the sysctl command:

sysctl hw.physmem

This will output the total physical memory in bytes. For human-readable format:

sysctl -h hw.physmem

For more detailed memory information including slot configuration (requires root privileges):

dmidecode -t memory

Sample output showing DIMM slots and sizes:

Handle 0x1000, DMI type 16, 15 bytes
Physical Memory Array
    Maximum Capacity: 64 GB
    Number Of Devices: 4

Handle 0x1100, DMI type 17, 21 bytes
Memory Device
    Size: 16 GB
    Form Factor: DIMM
    Locator: DIMM0

The top utility shows real-time memory usage including total RAM:

top

Look for the "Mem" line in the header:

Mem: 1481M Active, 647M Inact, 274M Wired, 128M Cache, 247M Buf, 684M Free

For scripting purposes, combine commands with grep:

sysctl -n hw.physmem | awk '{print $1/1024/1024 " MB"}'

Or for just the numeric value in MB:

sysctl -n hw.realmem | awk '{print int($1/1024/1024)}'

For server administrators needing DIMM details:

pciconf -lv | grep -A4 memory

This shows memory controller information and can help identify ECC/non-ECC configurations.