I have had dwarf sag in 3 tanks under 3 different types of lights.
Under dual t5 NO it grew the slowest. It's a shrimp tank and I don't do any ferts except for the occasional root pellet for the crypts nearby. May 1 or 2 runners in the last few months. Stays green; minimal growth.
Under LEDs (Finnex fugeray) the growth was moderate. The tank was overcrowded plant wise and I suspect that it had a lot of competition for nutrients and light. Root pellets, liquid ferts, and DIY CO2. It was in the tank for about 9 months and the number of plants doubled at least.
Under a pair of 13w CFLs (plus direct sunlight because it is near a window) they are sending out new runners every 2-3 weeks. No CO2 or root pellets; daily dry ferts. This tank is a "not sure what to do with these plants so I'll throw them in here" type of tank.