HI Toni, there aren't any controls for buffering outside of what Storyline does itself. I guess your users are seeing the spinning loading icon for long periods.
I would start by taking a look at the assets within the module and seeing if they can be compressed further, and ensure you are using the correct formats. Ignore the following if you've already done this.
For example, minimise the use of PNGs on photographs if they do not have any kind of transparency. Change to JPG instead.
Use tools such as TinyPNG to further optimise JPG and PNG images.
Check the published output of the images and order by file size. Look out for large files, for example, > 100kb. You might also find images with small dimension such as icons etc can be further compressed. I sometimes find an icon that is 15kb, can be reduced to under 1kb. All of these small gains can make a big difference.
The biggest culprit is usually photographic images being deployed as PNG when they don't need to be, or JPG images that have not been compressed.
The other obvious culprits are audio and video files.
Cheers,
Sam
