Why Am I Getting Low FPS with a High-End PC?

Hey everyone,

I'm having some frustrating issues with low FPS in various games, despite having a high-end setup that should be performing better. Here are my specs:

- Intel i9-10900K
- NVIDIA RTX 4080
- 64GB DDR4 RAM at 3887 MHz (I had to manually tune it since XMP doesn't work; it's rated for 4400 MHz)
- MSI Z590 Gaming Force motherboard (it's used and has some issues like non-functional SATA ports)
- 2 NVMe SSDs (one for Windows and one for games)
- 2x 32" monitors (240Hz, one set to 60Hz in vertical mode)

Here's how it's performing:
- No Man's Sky: ~100 FPS on planets, ~150 FPS in space with DLSS
- Warframe: 100-120 FPS (I used to hit 250-300 FPS with an RTX 2060)
- Minecraft (1.18/1.19): ~100-120 FPS, no shaders used
- Valorant and CS:GO perform as expected with full FPS

Even though I suspect a 10-15% CPU bottleneck, this doesn't seem right for an RTX 4080. The GPU usage rarely hits 100%, and temperatures are good.

Things I've done:
- Just did a fresh Windows install about a week ago.
- Cleaned and reinstalled NVIDIA drivers.
- Tweaked various settings in Windows (like disabling certain services and enabling game mode).
- Set power settings to max performance.
- I think my BIOS might be outdated since the motherboard is a bit sketchy to flash.

Any ideas on what I could do? Happy to share logs or benchmarks. It really feels like my GPU isn't being utilized to its full potential, and I'm not getting the performance I expect.