أنشئ حسابًا أو سجّل الدخول للانضمام إلى مجتمعك المهني.
make sure that the system you plan to purchase can be found on windowsservercatalog.com. That is where supported systems are listed.
As for the sizing, there is no way we can tell. You did not mention what sort of application you are talking about. You did not mention what sort of CPU, network, memory, or IO load the application will place on the system.
If you are purchasing the application for the users, you could most likely talk with the application vendor and get some recommendations there.
