> For the complete documentation index, see [llms.txt](https://docs.boostfordaz.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.boostfordaz.com/extras/top-tips-and-tricks/the-secret-of-the-cache.md).

# 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.