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Dark Hero z790 Strange m.2 Issue

Level 8

I am having an issue with my m.2 slots on my Dark Hero Z790 Board. My editing slowed down when using my 4TB Samsung 990 Pro. I ended up seeing the speeds cut to a small fraction of PCIE 4.0. I went and Bought 3 New SSDs to test and This is what I have found. It does not matter what SSD I put I put in M.2_2 it has the write speeds gimped for some reason. I had the top slot unoccupied since finding out about the Lanes on My GPU getting cut if I used it. Now I have all others slots populated and my New hard drive had the same exact issue. I tried running raid of 2 of the drives to help. I have paid full price for this board and I see now its listed for around 200. I think I may need an RMA but I literally have work piled up now. Stressed... Any Advice?


Level 17

Look at your drives in Device Manager - is write caching enabled?

Z690 Hero, 12900K, BIOS 3603, MEI 2407.6.1.0, ME Firmware, 7000X Case, RM1000x PSU, ASUS TUF OC 3090TI, 2 x 16GB Corsair RAM @ 5200MHz, Windows 11 Pro 23H2, Corsair H150i Elite AIO, 4x Corsair RGB fans, 3x M.2 NVME drives, 2x SATA SSDs, 2x SATA HDs.

Super Moderator

Hi @greggyp89 

I would check firstly that you haven't knocked the Alternate PCIE Mode Switch to GEN3.0



13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090