Taichi X470 + M.2 NVMe disk on M2_2- speed issue

Hi

I connected new SSD NVMe disk (WD Blue SN570 1TB) to second M2_2 port (on first port M2_1 is Samsung EVO Plus NVMe which works 3500MB/s).

I made a speed tests and this and have performance issue. This disk reaches only around 400 MB/s
Crystal Disk Info says that disk is connected to NVM Express interface.

To my MB are connected GPU and two PCIe cards (USB 3.0 extension and Firewire card which is now disabled on PCIe 5 port)

I have Ryzen 5900X CPU.

[Read] SEQ    1MiB (Q= 8, T= 1):   416.206 MB/s [    396.9 IOPS] < 20102.26 us> SEQ    1MiB (Q= 1, T= 1):   402.971 MB/s [    384.3 IOPS] < 2601.27 us> RND    4KiB (Q= 32, T= 1):   406.129 MB/s [ 99152.6 IOPS] <   312.53 us> RND    4KiB (Q= 1, T= 1):    57.221 MB/s [ 13970.0 IOPS] <    71.46 us> [Write] SEQ    1MiB (Q= 8, T= 1):   410.024 MB/s [    391.0 IOPS] < 20382.23 us> SEQ    1MiB (Q= 1, T= 1):   404.667 MB/s [    385.9 IOPS] < 2590.06 us> RND    4KiB (Q= 32, T= 1):   304.547 MB/s [ 74352.3 IOPS] <   429.84 us> RND    4KiB (Q= 1, T= 1):   118.159 MB/s [ 28847.4 IOPS] <    34.55 us>

Any Idea what is wrong? I found that X470 Taichi supports

"- 1 x M.2 Socket (M2_2), supports M Key type 2230/2242/2260/2280 M.2 PCI Express module up to Gen2 x4 (20 Gb/s)*"

While it's not even reach typical SATA6 bandwidth.

Thank for help
Lukas