In this case the only interesting comparison is the relative speed of the benchmarks under LV 6.0.2 compared to LV5.1.1. These compare the same VIs on the same machine under similar circumstances. I attempted to have my Mac in identical states for two tests.
In general, LV 6 is faster than LV 5. There are some areas where LV6 is a bit slower such as converting strings to integers, and for updating the classic meter indicator but for calculations (see the floating point performance graph) it has been speeded up substantially. The file I/O for reading has improved substantially also.
The following graphs are representative of the speed differences I found. The green graph is LV 6 and the red line is LV 5. The ordinate is in relative time so that a smaller time is better. All times are relative to the time in LV 5.
All tests were run on a Power Computing Mac clone with a 400 Mhz G3 upgrade card, System 9.1, extensions off, Virtual Memory off. [an error occurred while processing this directive]