As no NVMe PCIe SSD is found on the tested hardware lists (click here for them) and because you ensured your system BIOS/firmware (as a whole) is at the latest, indeed, we, then, suggest the following:
1. Test the SSD on the different PCIe* slots.
2. If the situation still persists, please, check with the NVMe PCIe X4 SSD manufacturer to see if they officially validated it on the Intel® Workstation Board W2600CR2, and if so, what suggestions they have on their own, based on their own tests.