Sonnet Fusion Dual PCIe Card & Mac Pro 2023

I've had my Mac Pro 2023 since the Summer of 2024 configured with the Sonnet Dual Fusion Card and 2x Samsung U.2 1.9TB SSDs (PM9A3).

From Day1 the performance of the SSDs was weird. According to the Blackmagic Disk Speed Test App - WRITE was around 2700MB/s / READ around 25MB/s??? I've had long discussions with Sonnettech and they have tried to convince me that the PCIe card is ok. According to the Samsung Magician App, the performance of my U.2 Samsung SSDs are fine - WRITE 2675MB/s READ 3225MB/s.

Unfortunately when I come to run Windows 11 (ARM) via Parallels from one of these SSDs the performance is awful, W11 refuses to load major updates and often crashes with the blue screen of death.

I was about to return my Sonnet Dual Card to Sonnet for testing and bought a StarTech single U.2 PCIe card to tide me over. Guess what? Exactly the same problem - OK WRITE / Awful READ speeds via the Blackmagic Disk Speed App. OK WWRITE & READ via Samsung Magician but Windows 11 still runs like a dog...

Something is wrong but what? Is it the Sonnet Card, the Samsung SSDs, or my Mac Pro M2?