There's an interesting scenario with NVIDIA drivers power limiting GPU when there's monitoring or tweaking software enabled while express or custom (with factory reset) installing newer NVIDIA drivers. The installer basically puts the GPU in limp mode and restricts the maximum power limit.
So before applying new driver it pays to always check if you closed these programs first.
If you already noticed a performance drop of late and have been using MSI Afterburner for example running in the background then this is why