Hello, some components such as RAM and PSU that I want are only available via 3rd party sellers in Amazon. Newegg has components sold and ship by Newegg. However, on the internet, I read some posts from customers that Newegg sometimes ship components used by other customers as if they were new. In this case, which site should I buy the components? Do I have to worry? How do I know if the RAM have been used or opened by other customers?