Windows systems in general
Windows systems tend to use more RAM than linux. We provision Windows servers from 1GB RAM and up. If you only have 1GB of RAM on your Windows VPS it may have issues running multiple applications. You can always upgrade resources as required, but as a general rule we would recommend 2GB of RAM minimum for a production server. If running MS Exchange you would want 8GB RAM and 4 CPU Cores, an SQL server needs a minimum of 4GB of RAM and 2 CPU Cores.