Feature request: support more than 3.584 MB guest RAM (64 bits hosts)

[Patrick Julien]

Even when running the 64-bit version of VirtualBox on a 64 bit version of Windows Vista, it's not possible to allocate more than 3GB of memory to the guess operating system.

[Sander van Leeuwen]

Which method are you using for running the VMs? My VirtualBox.exe has the LARGE_ADDRESS_AWARE flag set and I can use up to the max (3.584 MB). Vista 64 host with 16 GB ram.

[Patrick Julien]

I too, can set the maximum to 3.584MB with a Vista 64 bit host with 32GB of RAM.

However, it's possible for the process to access up to 8TB of virtual address space. Looking at the article that I posted, the testlimit64 tool was able to reserve(not commit) 8TB of virtual memory before running out.

I am trying to find the switch that makes this possible.

[Patrick Julien]

According to the information I have found, IMAGE_FILE_LARGE_ADDRESS_AWARE is all that is needed on a 64-bit host to have access to an 8TB address space on 64 bit.

So why is virtual box limiting the memory limit of a guest to 3.584MB then?

[Sander van Leeuwen]

Because we don't allow more at the moment. That has nothing to do with executable image flags. We will allow for more in the near future.

[Patrick Julien]

Replying to sandervl73:

Because we don't allow more at the moment. That has nothing to do with executable image flags. We will allow for more in the near future.

OK then, sounds good.

[Sander van Leeuwen]

Note that we'll probably not implement this on 32 bits *hosts*.