Using 14.7, I noticed that on my system if I don't strap a card, the rxboost command doesn't take effect for that card either.

For example, -strap 1,1 -rxboost 30,20 works fine and applies the new refresh timing to both cards.

Bit if I use, -strap 0,1 -rxboost 30,20 the strap is skipped, but so is the rxboost for card 0.

I never see -rxboost applied on card 0 on screen or in the log.  I think it's just a command line processing error.