Hello @Customer5492,
thank you for purchasing our Premium plan. Yes, by default each Premium website or Premium subdomain has 512MB RAM limit. Maybe this may seem like small amount but it's important to note this is dedicated RAM only for your application. Most competitors offer smaller amount of RAM or offer VPS where RAM is shared between operating system, website, subdomain, database, email and other services. In our hosting this memory is not shared.
In our Control panel you can always see how much RAM your application consuming and RAM limit can be increased if needed, but currently this option is not available in Control panel and you must contact us via Support ticket in Control panel.