I have updated today to Monterey a bit earlier, obviously though the beta programme. I have an i7 with 5300M and I'm a bit disappointed by the new low power mode feature. I'll explain with some details below.
Setup: 2 x DELL P2419HC monitors connected via USB-C
Low Power Mode OFF
- Clamshell mode - 13-15W
- Lid Open - 13-15W
Low Power Mode ON
- Clamshell mode - 3-5W
- Lid Open - 5-7W
In BigSur in Clamshell mode I was getting 5-7W without compromising on CPU performance. I don't know about you but if your using clamshell you might get the same results as me, a bigger power draw (13-15) for the same way of working. If you're working with your lid open you'll definitely see some improvements.
LE: I was getting those numbers on idle.