virtualbox.org

Hi to everyone

I have a 32bit Win7 on a Quadcore Intel with 6GB physical RAM, using 3GB (as usual for 32bit)

Question:
If I install a 64bit Win 7 guest on Virtualbox can I access and use the remaining 3 GB RAM for it ?
Intel VT-x is activated.

I'm afraid not. A VM is allocated system resources by the host OS, just like any other host app. The host OS can't allocate resources it knows nothing about.

p.s. The limit for a 32bit flat memory addressing scheme is 4GB, not 3GB. On a physical host the BIOS and some hardware devices grab some of that, so the main OS would typically have around 3.5-3.7GB actually available for use.

Also, Win32 logically separates the 4GB address space into 2GB for system and 2GB for user, so an application (e.g. the VM host process) actually can't allocate more than 2GB. There's a boot option to make the split 1GB:3GB.

Even on 32bit hosts that support PAE, there would typically be a limit on how much a single application can receive. That limit would depend on the host, but will be similar to the numbers already discussed.

Thanks mpack for answer.

I will upgrade to 64bit Win7 and later move to virtualbox