Performance in games varies with each startup

[Stryker041]

my games' performance varies with each startup and its weird. On one day, my games work fine and with no problem, but then some other day my game will freeze once for about 3 seconds or have fps drops. My rig is i3-4160, Nvidia GTX 750 ti OC, and 8 GB of ram. Can anyone tell me what might be the culprit? its really hard to pinpoint the cause. Ive updated the drivers, defragged my harddrives, scanned for viruses, and cleaned out my PC physically. I used to have a GT 730 as my GPU but one day my games' started having fps drops and as time went on it became unplayable, but on certain days theyre fine. But after buying the GTX 750 ti my games run better but i fear that one day my games will become unplayable after a few months again.

 

[geofelt]

Run malwarebytes free edition.

What is your cpu temperature at idle?
It should be 10-15c. over ambient if it is mounted well.

Activate task manager/ performance monitor.
When the freeze occurs, try to identify any process that is using lots of cpu or I/O

Regardless, if you do not have a ssd for windows, it is time to do so. Everything will be quicker.

 

[Stryker041]

my CPU temps are at 30 C idle, and rises up to 40+ when playing. How do i identify which process is using lots of CPU? and if i do find it what should i do