The CrystalDiskMark sequential 32 queues and 1 thread test provided similar results across all three operating systems using the Samsung SSD 850 Pro 512GB.
The 4K 32 queues and 1 thread test showed Windows 10 and 8.1 delivering similar read performance while Windows 7 was a fraction slower. That difference was amplified when looking at the write performance, here Windows 7 was noticeably slower.
The sequential performance was again very similar as Windows 10 and 8.1 provided almost identical performance, Windows 7 was again just a fraction slower.
Finally the 4K performance with the Samsung SSD shows all three operating systems delivering similar results, this time Windows 7 is slightly faster than Windows 10.
Storage Performance with the Samsung SM951 NVMe SSD
The following tests were conducted using the Samsung SM951 256GB NVMe SSD installed in the Ultra M.2 slot on the Asrock Z97 Extreme6. Note we were unable to get the SM951 NVMe working in Windows 7.
Windows 10 and Windows 8.1 show similar SSD performance when using an M.2 NVMe drive.
Again Windows 10 and 8.1 are evenly matched when measuring 4K Q32T1 performance.
The sequential results are also much the same.
The 4K performance provides mixed results. Windows 10 was a fraction better when measuring read performance while Windows 8.1 was much better when comparing write performance.