Just noticed that performance degrades as well, when opening a home with sh3d-5.3(jre1.6.0_45) that has been previously saved by sh3d-5.3. That's to day, I experience only "good" performance by using the old JRE with 5.2 version homes.

Now I'm wondering whether the performance issue could be ...

But as you think that slowness doesn't come from the 3D part, I'll see if it comes from the Java version itself.

I can confirm that there is no performance impact anymore after switching from bundled jre8 to (5.2 bunndled) jre1.6.0_45.

After several issues with SH3D 5.2 on Linux (Graphical issues and crashes with WebStart, long startup time with installer), I'm glad to see after some testing that the 5.3 release supposes to be much stabler on Linux.
I can confirm the notable performance decrease - although more related to the plan ...