OK - Here's the response from ASRock tech support:
"Dear ASRock Costumer,
The jumpers are related to RAM adjustment only .The relation bvetween the cpu and ram the manual mention is about if you install the AM with CPU, but if you want to OverClock the CPU you can do under BIOS >CPU comfiguration CPU Frequency (auto ) you can change to the desired speed to overclock.
ASRock Support"
I think(?) I get it. The jumpers lock down the RAM if you plan on OC'g the CPU. Hopefully, this will help any other folks who might pick up an ASRock board. This is my first. I wish MB makers would hire us to proof read and edit the manuals before they go to print.
- Bill
(An' I ain't no "Costumer" - lol!)