Is this one of the Y50s with the Western Digital SSHD? There's a known issue with them due to the ridiculously short head parking timeout WD puts on them. Every time the head parks, the next time Windows tries to access the disk, it will freeze the entire computer for about a second while it waits for the heads to unpark. (Ignore the "Solved" flag - that's just Lenovo trying to get you to think the problem doesn't exist.)
https/forums.lenovo.com/t5/Lenovo-P-Y-and-Z-series/Y50-70-Windows-regularly-freezes-when-1TB-SSHD-is-spinning-up/td-p/1809301/page/4
https
/community.wd.com/t/nasty-intelli-park-on-wd-scorpio-blue-1t-2-5/15519/4
To test if this is the issue, create a new file named test.bat containing the following:
:repeat
@echo %RANDOM% > tmp.txt
ping -n 8 127.0.0.1 > NUL
goto repeat
Then in a command prompt, run test.bat and leave it running. It writes a random number to the disk every 8 seconds, preventing the heads from parking. If this causes the lag/stutter to disappear, then you are indeed suffering from this problem.
■You used to be able to fix it with a program WD put out called wdidle3.exe. But they redesigned their website a year ago and the page hosting it disappeared. You might still be able to find it somewhere.
■You can just run the above batch file whenever you game.
■You can use CrystalDiskInfo and disable all the power management (APM) settings on the drive (move the slider to the right til it says FEh). It'll probably cost you a few minutes of battery life, and on mine it would reset every few reboots and I'd have to do it again.
■You can just replace the WD drive with a different drive (preferably a SSD). Please note that all the laptop WD green, SSHDs, and I suspect blue drives suffer from this short head parking timeout.
http/crystalmark.info/download/index-e.html