# The Secret of the Cache Once you are connected to a GPU and its supporting virtual server running Iray Server on Boost for Daz, and you hit the [Render ](/using-boost-for-daz/rendering-with-boost-for-daz/rendering-the-daz-project.md)button in Daz Studio, Daz Studio prepares a 'render package' before uploading to Boost for Daz for rendering. This [upload ](/using-boost-for-daz/rendering-with-boost-for-daz/uploading-render-package.md)package includes the .duf file as well as all the assets and additional elements such as textures, shaders, instances etc. that will be required to render the scene - just as you intended. Once uploaded, the render package is stored in a cache on the Iray Server virtual machine on Boost for Daz - before the rendering process is started. The way Daz Studio ensures that it has all the elements needed for rendering your scene is through the *hash* calculation process. During the hash process, Daz Studio queries the Boost for Daz virtual server to see if any render package elements already exists in the cache. If it it doesn't, it marks that particular element for upload. If it does, it does not upload it. ![](/files/LD52cRv78jWWLtXY85T1) Now that's pretty cool (if we say so ourselves). Because after that first upload, only any *changes* to your scene - for example, a new pose, or lighting change etc. - is marked for upload. So when you hit Render the next time, only those changes are sent up to the cache on Boost for Daz and the render process completes much faster. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.boostfordaz.com/extras/top-tips-and-tricks/the-secret-of-the-cache.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.