TerraMaster F4-425 Plus and F2-425 Plus specifications:

    SoC – Intel Processor N150
        CPU – Quad-core “Twin Lake” processor @ up to 3.6 GHz (Turbo) with 6MB cache
 
        Hardware transcoding
            F4-425 Plus – H.264, H.265, MPEG-4, VC-1 up to 8K@60fps
            F4-425 Plus – H.264, H.265, MPEG-4, VC-1 up to 4K@60fps
        TDP – 6W to 15W (Configurable in BIOS/UEFI)
    System Memory (DDR5 non-ECC SODIMM, expandable up to 32GB)
        F4-425 Plus – 16GB
        F2-425 Plus – 8GB
    Storage
        F4-425 Plus – 4x SATA bays for 3.5-inch SATA HDD and/or 2.5-inch SATA SSD/HDD (up to 30TB/drive), hot swapping support
        F2-425 Plus – 2x SATA bays for 3.5-inch SATA HDD and/or 2.5-inch SATA SSD/HDD (up to 30TB/drive), hot swapping support
        Both – 3x M.2 2280 NVMe SSD slots (PCIe 3.0 x1, up to 8TB each)
        Max raw capacity:
            F4-425 Plus – up to 144TB (4x HDD + 3x M.2 SSD)
            F2-425 Plus – up to 84TB (2x HDD + 3x M.2 SSD)
        RAID support – RAID 0/1/5/6/10, JBOD, Single, TRAID / TRAID+
        File systems
            Internal Drive – BTRFS, EXT4
            External Drive – EXT3, EXT4, NTFS, FAT32, HFS+
    Video Output – HDMI 2.1 (Terminal output only, not for video)
    Networking –  2x 5GbE RJ45 ports with link aggregation (SMB Multichannel, Bonding modes)
    USB
        3x USB 3.2 Type-A ports
        1x USB 3.2 Type-C port
    Misc
        F4-425 Plus – 120mm smart fan with smart/high/mid/low speed modes
        F2-425 Plus – 80mm smart fan with smart/high/mid/low speed modes
        Noise level – 20–21 dB(A) (measured at 1m, HDD standby)
        Supports direct data drive mounting without reformatting
        TRAID technology – up to 30% faster read/write performance
        Hardware-accelerated 8K/4K video transcoding
        Aluminum-alloy chassis

 the new 4-bay F4-425 Plus goes for $569.99,
while the 2-bay F2-425 Plus sells for $399 on Amazon,


plutôt pas mal niveau spec