I wouldn't worry too much at getting 180 fps. That's great if your PC can reach that level of performance, but it's not good to keep it running that for long sessions. That can shorten the life of your PC quite a bit, unless you have some serious cooling going on. I cap my older system at 40 fps for SL/OS and most other 3d games I play. Mirrors work fine for me and I can manage about 25 fps with them on at medium settings.

I understand the struggle with older computers with less than ideal graphics. After 18 years in virtual I still remember the day years ago when someone took a pic of one of my lamps and I saw glow for the first time, but when I went into my graphics settings on my laptop it was grayed out. From that point on I started gradually improving my systems a little at a time to get where I'm at now. I'm still well aware that there are some who will not be able to see everything I add to a build but hopefully it inspires them.

I love that spaceship :-)

One mirror does decrease fps, but when I'm running ultra graphics at 179 fps the drop isn't noticeable. The really interesting discovery was that doubling or tripling the number of mirrors produced no additional drop in fps at all. To be honest, I have almost zero interest in placing out mirrors, but what pbr IS good for is much better surface lighting when pbr materials are used on objects, especially metals and floors. The lobby of my store, Lunaria Emporium, looks far better now than it ever did with the older FS viewer. You can see pbr at work there on multiple surfaces.