Random Murderer, I think, there will be both modes - fast and smooth.
Today again measured the power consumption :
1 - 3DMark11 (Extreme level)
2 - OCCT ("Power supply mode" until 2 minutes)
HD7950 worked absolutely normal with 2500k and long riser.
But sometimes are BSODs, because voltage after riser is 11,7 volt.
So, i added short fat wire for voltage boost.
I was educated in the Soviet Union (1985-1989).
In the 90's I was a dealer in a casino, then served the slot machines, then repaired the computer equipment ...
This is a normal career for almost any Soviet engineer )))