On MacOSX, if you have installed macports with the package installer, you may encounter the sudo: port: command not found problem.
Macports binaries are installed in /opt/local/bin, so you just need to add this path to your PATH environment variable. Example with your user, add to your $HOME/.profile :
export PATH=$PATH:/opt/local/bin
You can source your profile file to [...]

The dmidecode command gives you all informations available about your memory.
With the special parameter “-t 16″, you can see the maximum (physical) memory that your server can have:
$ dmidecode -t 16
# dmidecode 2.8
SMBIOS 2.4 present.

Handle 0×1000, DMI type 16, 15 bytes
Physical Memory Array
Location: System Board Or Motherboard
Use: System Memory
Error Correction Type: Multi-bit ECC
Maximum Capacity: 32 [...]