12 and 9 are way different then your stated 15 and 20.
While the new "Vapor X" technology cooling seems promising - I don't feel it is fully required yet, especially with a decent cooling case. The design seems a bit lacking just to compact it into 1 slot instead of 2 slots.
Phase change cooling (what vapor x is designed on) is a newer thing over all - you can make your whole system Phase Cooled if you wanted to and get the similar changes in temps and lower "noise levels".
While the new "Vapor X" technology cooling seems promising - I don't feel it is fully required yet, especially with a decent cooling case. The design seems a bit lacking just to compact it into 1 slot instead of 2 slots.
Phase change cooling (what vapor x is designed on) is a newer thing over all - you can make your whole system Phase Cooled if you wanted to and get the similar changes in temps and lower "noise levels".