8gb ram in 32bit operating system

Solution 1:

Replace your Windows 7 host from 32-bit to 64-bit and this is the only solution.

In a Windows (exclude servers) 32-bit operating system there is no way to assign address more than 32-bit (and also some reserved by other hardware), so your 4.3GB RAM will be totally invisible to VM.

Solution 2:

According to the official Microsoft documentation, Windows 7 ("all supported releases", whether 32-bit or 64-bit), support from 8GB (Home Basic version) to 192GB (Professional, Enterprise and Ultimate). This depends not on the release, but on the CPU architecture (32-bit, or 64-bit, which is what most (all?) desktop and laptop CPUs manufactured within the past 5 years have, being them Intel of AMD, despite the confusing "amd64" name).

Limits on physical memory for 32-bit platforms also depend on the Physical Address Extension (PAE), which allows 32-bit Windows systems to use more than 4 GB of physical memory.

Memory and Address Space Limits

The following table specifies the limits on memory and address space for supported releases of Windows. Unless otherwise noted, the limits in this table apply to all supported releases.

╔════════════════════════╦══════════════╦══════════════╗
║        Version         ║ Limit on X86 ║ Limit on X64 ║
╠════════════════════════╬══════════════╬══════════════╣
║ Windows 7 Ultimate     ║ 4 GB         ║ 192 GB       ║
║ Windows 7 Enterprise   ║ 4 GB         ║ 192 GB       ║
║ Windows 7 Professional ║ 4 GB         ║ 192 GB       ║
║ Windows 7 Home Premium ║ 4 GB         ║ 16 GB        ║
║ Windows 7 Home Basic   ║ 4 GB         ║ 8 GB         ║
║ Windows 7 Starter      ║ 2 GB         ║ N/A          ║
╚════════════════════════╩══════════════╩══════════════╝