By default, laptops sold on RetroFreedom.com come with 4GiB RAM. If you wish to have 8GiB RAM, order this product with your laptop. This will allow you to run more applications at the same time. If you also want bigger, faster storage, you can buy an SSD+8G kit: https://retrofreedom.com/product/8g-ram-and-480g-ssd-upgrade/
You can also order this product on its own. The module shipped is guaranteed to work on Libreboot X200, X200 Tablet, T400 and W500 sold on this website.