Out of curiosity, I ran some comparison between connecting my RPI4 to a USB port on a power strip, and to a QC power adapter. There is a clear winner.
On both power source, I tested with sysbench with these parameters:
❯ sysbench cpu --threads=16 --time=180 run
When my RPI4 is connected to the Targus Smart Surge 6 power strip, the kernel reported under voltage warning, and the red LED is off. System seems to be working, and sysbench completed without problem.
When my RPI4 is connected to the quickcharge USB power adapter, the red LED is always on. For those who do not know, the red LED indicates if the input power is under voltage. It will stay on if voltage is good. Otherwise it blinks or turn off completely.
The interesting part is the benchmark results.
|On PowerStrip||On QC adapter|
|Sysbench events per second||1775.59||4990.81|
|Rated power output||4.8A||5v 2.0A|
|USB power meter reading||4.89v 0.63A||5.33v 0.9A|
So on a proper power source, the PI performs much much better! It seems RPI4 needs 5+ volt to operate properly. The power strip cannot deliver that and the 4.8A rating is just meaningless.
If you are not getting the expected performance from your RPI, check your power source.
I replaced my Targus power strip with a Momax Oneplug 11-outlet power strip and its usb-c port provides sufficient voltage for RPI4. The USB power meter measures 5.09v output. It even comes with a PD port which I can quick charge my other peripherals.