Having write speed issues with my old Sandisk Extreme Pro 512Gb and brand new 1Tb keys !. Write speed initially around 200Mb/s but quickly drops to 80-100 Mb/s after a three seconds which is unnaceptable. Tried NTFS (4k alloc) and ExFAT (256K alloc) formats to no avail, rebooted PC etc (Windows10). Using a high end Intel PC with fast USB3 ‘SS-10’ port. Source file on a VERY fast M2 drive (around 5Tb/s). Changing drive policy from ‘quick removal’ to ‘better performance’ gives the expected speed boost but only for a few seconds before dropping again to around 80-100Mb/s. Yes latest drivers and Windows updates applied.
What’s happening here Sandisk ?