As Citrix Provisioning Services has begun to play a greater role in XenApp and XenDesktop implementations, many discussions have been had on proper sizing of Provisioning Services from a network, CPU and storage perspective. However, most recommendations have left out guidelines for proper sizing of the one of the most crucial components; memory (RAM). This white paper will detail why RAM not only in the Provisioning Services servers, but RAM within the target devices is one of the most important scaling considerations for a successful Provisioning Services deployment. Additionally, this paper will discuss the impact of RAM on storage considerations and which storage options provide for optimal performance. What this white paper does not cover is storage best practices and IOPS requirements for shared target devices.