Does memory need to be installed in same-size pairs in the Mac laptops of recent years such as MacBookPro8,1? In the old days memory needed to be installed in pairs of equal size such as 2 X 2 gigs for a total of 4 gigs. Installing say one 2 gig module and one 4 gig module for a total of 6 gigs would either not work or would cause slower operations than if a same size pair were installed.

Is that still the case?

For example an a MacBookPro8,1 (Late 2011) might we install one 2 gig module and one 8 gig module for a total of 10 gigs without problem nor penalty?
According to Apple's official site:


  For best performance, fill both memory slots, installing an equal memory module in each slot.


I believe it is technically possible to install RAM of different sizes, but Apple doesn't officially recommend it.