you can try like this
Add a Reference to System.Management.
private static void DisplayTotalRam()
{
string Query = "SELECT MaxCapacity FROM Win32_PhysicalMemoryArray";
ManagementObjectSearcher searcher = new ManagementObjectSearcher(Query);
foreach (ManagementObject WniPART in searcher.Get())
{
UInt32 SizeinKB = Convert.ToUInt32(WniPART.Properties["MaxCapacity"].Value);
UInt32 SizeinMB = SizeinKB / 1024;
UInt32 SizeinGB = SizeinMB / 1024;
Console.WriteLine("Size in KB: {0}, Size in MB: {1}, Size in GB: {2}", SizeinKB, SizeinMB, SizeinGB);
}
}