I'm running into an issue with a particular SSD when benchmarking it outside of Safe Mode. I've been trying to disable various startup services and processes to determine the cause, but to no avail.
When fresh installing a 2015 version of Windows 10 Professional with no further installations of drivers or updates, I've achieved scores in Crystal Disk Mark matching expectation. Running the same fresh install in safe mode yielded even higher results, but this discrepancy is understandable due to background system processes that may exist in Regular boot of even a fresh installation.
That said, after running windows updates and nothing more, 4KiB results are halved or worse in Normal boots. Safe Mode restores this performance to around 80% of expectation.
I've performed the above tests with Windows 10 Enterprise, Windows 10 Professional (both to current latest release updates), Windows 10 Professional (2015 installation, no updates), Windows 10 Professional (2015 installation, full updates).
With the exception of base installation 2015 Windows 10 Professional (no updates), all benchmarks result in ~40% 4KiB speeds (tested via both CrystalDIskMark and AS SSD) while running in Normal boot - base installation, no supplemental programs/drivers added on.
My conclusion at the moment is that this may be caused by some kind of Windows update/patch/windows provided drivers. Given that safe mode yields excellent results in all tests, the base drivers from a fresh installation should work just as well for a Regular boot (to my knowledge). Do also note that the 2015 run in Regular boot also ran nearly matching Safe Mode results - I imagine this points to a recent Windows update causing this issue.
I have tested this same SSD across multiple laptops and desktops (all running windows 10 Professional - up to date) - all yielding the same pattern of performance drop in Regular boot vs Safe Mode.
For reference, the primary system configuration:
Gigabyte Aorus Z390 Xtreme
Intel i9 - 9900k
EVGA 1080 TI SC2 Hybrid
Intel Optane SSD 905p 1.5TB - Add in Card (This is the SSD that is causing the aforementioned issues)
Samsung 970 Pro 1 TB M.2 SSD x2
Corsair Dominator Platinum DDR4 3200MHz - 16GB x 4
Corsair AX1600i PSU
I've contacted Intel to no avail, being referenced datacenter articles for a different line of SSDs. Any help or advice would be greatly appreciated. Thank you kindly in advance.