The Mac Mini 6,1 (2012) base model ships with 4GB of Memory in a 2x2GB 1600Mhz 204 pin SODIMM configuration. 4GB as it turns out, is a little inadequate for running Ubuntu, FreeBSD, CentOS and XP simultaneously. The Linux VMs seem to need more than 512MB to compile kernels and XP is super sluggish with anything less than 1GB.