The Windows API function GlobalMemoryStatusEx
can be called with p/invoke:
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
private class MEMORYSTATUSEX
{
public uint dwLength;
public uint dwMemoryLoad;
public ulong ullTotalPhys;
public ulong ullAvailPhys;
public ulong ullTotalPageFile;
public ulong ullAvailPageFile;
public ulong ullTotalVirtual;
public ulong ullAvailVirtual;
public ulong ullAvailExtendedVirtual;
public MEMORYSTATUSEX()
{
this.dwLength = (uint)Marshal.SizeOf(typeof(NativeMethods.MEMORYSTATUSEX));
}
}
[return: MarshalAs(UnmanagedType.Bool)]
[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
static extern bool GlobalMemoryStatusEx([In, Out] MEMORYSTATUSEX lpBuffer);
Then use like:
ulong installedMemory;
MEMORYSTATUSEX memStatus = new MEMORYSTATUSEX();
if( GlobalMemoryStatusEx( memStatus))
{
installedMemory = memStatus.ullTotalPhys;
}
Or you can use WMI (managed but slower) to query TotalPhysicalMemory
in the Win32_ComputerSystem
class.