OK, looks like I'm first here
I'll show you mine if you show me yours

Here are my results before and after using jkdefrag's Registry Optimization and the difference in % :
HKEY_LOCAL_MACHINE
Average random access time per entry 0.012500 ms 0.012810 ms 2%
Average random read time per byte 0.000200 ms 0.000210 ms 5%
HKEY_CURRENT_USER
Average random access time per entry 0.009380 ms 0.009370 ms 0%
Average random read time per byte 0.000040 ms 0.000020 ms -50%
HKEY_CLASSES_ROOT
Average random access time per entry 0.027350 ms 0.027180 ms -1%
Average random read time per byte 0.000470 ms 0.000470 ms 0%
HKEY_CURRENT_CONFIG
Average random access time per entry 0.006090 ms 0.006250 ms 3%
Average random read time per byte 0.000000 ms 0.000000 ms 0%
HKEY_USERS
Average random access time per entry 0.010000 ms 0.010160 ms 2%
Average random read time per byte 0.000030 ms 0.000040 ms 33%
AVERAGE OF ALL HIVES
Average random access time per entry 0.013064 0.013154 0.7%
Average random read time per byte 0.000185 0.000185 0%
It actually made it
worse, if only by 0.7 %
But let me mention that I had run jkdefrag a couple of days ago, so that may explain the minuscule difference
I also tried to run Tuneup Utilities' Registry Defrag afterwards, but it told me that "my registry didn't need defragging"
In any case, it looks like you can at most improve your registry access speed by a millisecond ... hardly worth it
Thank you for the link, Mouser. It surely is an "enlightening" little utility.