The QNAP TVS-h1288X has two PCIe Gen 3 x4 slots

The TVS-h1288X is built for serious expansion — two PCIe Gen 3 x4 slots let you drop in 10GbE or 25GbE networking, SAS controllers, or M.2 NVMe adapter cards. If you’re building a high-performance QNAP setup that needs to grow, this is the chassis you want. The headroom is exceptional for a tower NAS.