Some see Firestorm 6 as slower then v5, others do not. But there is a design feature in FS that may bite you and have you thinking it is the viewer. It isn’t necessarily just your imagination. Seems if you alternate between 5.1.7 and 6.0.1 Beta and have them sharing cache, which seems like a smart idea, you may well see a slowdown.
The viewers apparently look for a cache they made and if they do not find it, they delete the contents of the cache folders and build a new cache. So, when you first run 6 and attempt to share 5’s cache it deletes the cache and begins reloading. If you switch back to 5 the process repeats and each time to switch between versions, at least according to one of the FS peeps I trust.
Looks like we need to use one or the other. I’ve been using 6 and I like it. I don’t see a reason to switch back and forth. But… if you feel the need to switch back and forth, I suggest you assign a separate cache to 6.
We also know the Lindens are looking at and possibly already working on revamping the viewer cache. I am expecting significant changes in 2019. I also suspect the FS Devs have their own ideas about improving the viewer cache. So hopefully, we will see a mix of cache improvements in this coming year.
What that can mean…
Cache improvements can reduce scene render time and up the Frames per Second (FPS). Keeping the various assets on your local storage (hard disk) and decrypted will free up CPU time and avoid download time. As the main work thread is pretty much a single task it has to wait on decryption and downloads. We know to a degree it will workaround some things and spin-off 20 or so supporting treads/tasks. (Ref)
As the decryption requires CPU time that is an FPS hit. Getting all the textures is less a problem as the viewer engine does draw gray things, working around missing textures. But it cannot draw a mesh object until it downloads the thing. It has to know where the vertices are to draw them. It is during this time that downloads are increasing the scene render time and decryption of assets is lowering FPS.
Those misshapen things that look like a triangle or squished sphere and then morph into a chair or something is the viewer trying to deal with partially downloaded things. We will hopefully see less of this with a better cache system.
If you are wondering about the present cache, you are in good company. A major part the stuff we see is cached on our disk now. If you open up your Viewer Stats (Ctrl-Shift-1 a toggle), you can see information about cache performance. The numbers are good. But when I return home it looks like little of my home has been cached and I wait for the scene to rebuild… every time I come home… in spite of a 100% cache hit rate. Obviously, there is room for things to improve.
Hopefully, the coming cache remodel will improve overall SL performance.