Very very weird issue

I bet you never heard of that... every time i turn on the computer, everything runs slow, very slow, like if in place of my Samsung 850 pro SSD, there would be a floppy disk unit... but, and this is the weird part, if I launch an utility called passmark performance test, immediately the pc get back performing normally... I really don't understand where the problem is... any chance for some help?

my pc spec.
Mobo ASUS P97 Pro
CPU I7 4790K
RAMM 16 MB DDR3 12800 Corsair
GPU ASUS Nvidia GTX790Ti
1 SSD Samsung 850 Pro 250 MB
1 SSD Samsung 850 Evo 500 MB
2 HDD WD 500 MB
Windows 10 Pro 64bit

I'm afraid it can't be the passmark utility, because I've installed it after I had notice of the problem at my PC; the purpose was try the sdd performances and other components to find out the cause of slowliness issue... ironically, as soon I launch the utility, the PC come back to normal performances... an of course the benchmarks are all OK...
To put it in simple words, the PC gets stuck, and utility unlocks the problem... but this is just a clue, the true question is why windows start and remain so turtle slow? how to investigate on this weird behavior.


PS: well, at least the utility has proven that it is not an hardware issue, and, seem to understand the problem is somewhere into the boot processing... but what it could be?

Are you able to enter in to Safe Mode and see how the computer runs there? If it runs as expected, then it is either a driver or some startup app.

Problem solved with the Media Creation tool downloaded from the link in the bottom here, it works fine, great tool indeed :)