The memory limit is because Zorro is 32-bit. oP Group is working on adding a 64-bit version, as noted here:
Quote
Features planned for the next releases:
Overcoming the 32-bit limit for training and backtests (Zorro S; in development).
https://zorro-project.com/manual/en/new.htm

www.vitaltrades.com - andrew@vitaltrades.com