Congratulations for another successful BIOS modding!
Your reverse engineering skills are really impressive!
Integrated UHD Graphics, no driver?
Write speed is so low, 738 MB/s, why?
Why don't you use latest CrystalDiskMark 8.0.5, it works OK in Win-XP?
May I ask you for few more speed tests, if possible, (with faster SSD), just for general comparison?
Try to shrink your SSD XP system partition and make new (NTFS) partition on the end, (split SSD on 2, or more, partitions), then run CrystalDiskMark on both partitions and make 2 pictures.
(I mostly use MiniTool-Partition-Wizard for disk management and works OK.)
Then try same test, on same board, same SSD(if possible), but with Windows-10 and make 2 pictures.
Please post all 4 results or 4 pictures..
From my experience, NVME can never get full max-top-speed on Win-XP, on system-partition, and can not understand why? And if you change NVME-driver, results are totally different. Could proper NVME-driver for XP and/or TRIM solve this mystery? Any dependencies to "Intel Rapid Storage Technology" possible for Win-XP?
(Does exist any Crucial NVME driver, (T700, T705), for XP?)