DDR4 Speed terminology: The difference between PC4-17066R and PC4-17000

[RAGAZ]

I have been googling for quite a while and cant seem to find the answer.

So... what is the difference between PC4-17066R and PC4-17000?
I am mainly interested about the "R". Does it stand for registered?

Also if I understand correctly the number itself arives from this equation:
DDR4 2133 x 8 = 17066 (well 17064 to be exact but I gues they just round it? and also the 17000 ?)

If someone who knows the answer would share it, that would be great bacause it is delaying my purchase. Thank you

 

[Tradesman1]

Yes the R indicates Registered and like with some other designations the 17000 and 17066 both indicate 2133 (they also use 17060)

 

[RAGAZ]

Hey thanx for the quick reply.

On a side note:
Is PC4-xxxxxR out of the question, for a x99 build with the i7-5930k, then?

 

[Tradesman1]

Check the mobos specs some take registered others don't