So after googling i see A LOT of people with the same problem. I've got a Seagate Firecuda 520 NVME 2TB Drive (On a MSI MPG X570 Gaming PRO CARBON WiFi) that's supposed to have read/write speeds of 5000 MB/s / 4400 MB/s. It worked just fine in the beginning but as of late i've been experiencing problems. I can't get write speeds over ~1 GB/s on the drive.
Reinstalled Windows Updated Bios Tried drivers from different vendors Updated chipset drivers Changed M.2 Slot on the motherboard Confirmed it's running on PCI-E Gen 4.0 X4
Swapped in another Seagate Firecuda 520 2TB and i've got the same issue Disabled/enabled write caching Read speed sits steadily at 5000 MB/s so the port is working correctly.
My other drive a MP510 PCI-E Gen 3 works fine and gives me +3000 MB/s write speeds.
Other people with the same issue: https://www.google.com/search?q=slow nvme speeds x570