>>107765533
If you have enough connectors for all 3090s and the instantaneous power draw upon pressing the power button is low enough that overcurrent protections are not tripped, then the answer is yes.
Whether or not the system is stable at the default settings is a different question.
Starting with Ampere NVIDIA GPUs start suffering from power spikes that can drain the PSU capacitors and crash the system.
And if you have 4 GPUs multiple power spikes will sooner or later align and make the problem even worse.
Notably a power limit does NOT fix this problem, you instead have to limit the maximum boost frequency of your GPUs using something like
nvidia-smi --lock-gpu-clocks 0,1000 --mode 1
In principle it should be possible to reduce the boost frequency of your GPUs low enough that they're stable but obviously this will come at the cost of lower performance (particularly prompt processing).