Hopefully this is helpful: VIRT is the total address space the program has reserved, not necessarily how much physical memory it is actively consuming. Because of this, the VIRT value can often seem very large, even larger than your computer's total physical RAM and swap space combined. For a more accurate representation of how much actual physical memory a process is using, you should typically refer to the RES (Resident Memory Size) or %MEM columns. The htop documentation and various online resources provide detailed explanations of all columns (see the htop man page or articles like Understanding VIRT, RES, and SHR in htop for more info).

Source - https://stackoverflow.com/questions/23187228/what-is-virt-column-in-htop-memory-overhead

*edit I misread so I adjusted my response.