NVIDIA GPU 3090 performance mode setting

In my experience its generally not possible with GeForce products. The GPU driver decides what performance state to put the GPU in according to its own heuristics.

For enterprise/data center products, you can “lock” the performance behavior to some degree following instructions like this.

There are a few other threads on these forums with related questions/information. Here are a few:

1 2 3. There are others as well that you can find with a bit of searching.