Question Computer gets slow after cpu upgrade

[rwp8197]

hello everyone, i got this trouble after upgrading my CPU
here's the specs:
CPU: Intel Pentium Gold G4560 (upgraded to i5 7600)
asrock b250
gtx 1050ti
2x4 ram 2666MHz
SSD SATA 240GB (system) and 2TB HDD
450W Bronze 80+ PSU
Win 10

i've upgraded from Pentium Gold G4560 to i5 7600 which is seems to work out fine, i checked on the BIOS and all the hardware were detected.
i've booted to windows without reinstalling because the CPUs were from the same gen. at first it runs smoothly, but after a minute it gets slow down (lagging) a lot, and got a not responding from opening any other apps such as Task Manager, and it even takes more than a minute to shut down completely.

do i have to do clean windows install? or is it possible that there's some hardware damage since the CPU that i bought was secondhand?
at the time i opened the CPU, it has some warranty sticker on the back of the CPU, i've tried to installed it but i got a "no signal" message, so i removed the stickers (a little part of the stickers are still stick to the back tho), and then the computer are able to boot, but it gets slow down after a minute

 

[sonofjesse]

I only buy CPU's from known friends. Where did you get this CPU?

Is your CPU over heating, newer/faster CPU's usually produce more heat.

 

[rwp8197]

i bought the CPU from an online store, which i think is reliable since i just built a new PC from this store
is this have something to do with part of the warranty sticker that left on the back side of the CPU
or is this have something to do with the cooler fan, the one that i bought comes with a cheap fake stock cooler, so i am using my old intel stock cooler
------------------------
update:
i've tried to boot up the computer again, and runs the task manager on the idle condition, it shows the CPU usage around 7-10% but only runs at 0,27 to 0,41 GHz.
based on this condition what is the main cause of this problem?

 

[uWebb429]

@rwp8197

Run ThrottleStop.

ThrottleStop 9.6 Download

ThrottleStop is a small application designed to monitor for and correct the three main types of CPU throttling that are being used on many lapto

www.techpowerup.com

Open Limit Reasons and check for BD PROCHOT. If you see this in red, try clearing the BD PROCHOT box on the main ThrottleStop window.

 

[LeviTech]

Check also the energy profile that you are using and the Maximum Processor State. It should be like the image bellow.