The total amount of memory that you can assign to all virtual machines running on a single host system is limited only by the amount of RAM on the host.
On 64-bit hosts, the maximum amount of memory for each virtual machine is 64GB. On 32-bit hosts, the maximum amount of memory for each virtual machine is 8GB. Workstation Pro prevents powering on virtual machines that are configured to use more than 8GB of memory on 32-bit hosts. Memory management limitations on 32-bit operating systems cause virtual machine memory to overcommit, which severely affects system performance.