Yes, there was some versions with slower movement, because there was some compiler options in my MS Visual C++ with wrong values. But I corrected these compiler options in 0.3.1.22 version and later. Anyway, I am going to compile all the viewer versions to compare them and to see the speed differences.
Now, I don't have a lot of time, because I'm in Dublin and tomorrow I'll travel to Prague for 4 days. I'll know Jeffrey Martin in Prague