Overclocking CPU, I need an advice Options

[♠ The Joker ♠]

My rig:
CPU: intel i5-2500k Quad Core 3,30 Ghz
GPU: Msi Gtx 970 Gaming 4GB
RAM: 8GB
OS: Windows 10 Home
Monitor: 1920x1080

Hello, I have done my 1st cpu overclock and the results were not according to my expectations. I overclocked 33 CPU Ratio to 40 so each core has 4,0 Ghz and CPU Core Voltage to 1150 V. I tried playing Witcher 3 Wild Hunt afterwards and there was 0 difference in performance, FPS was the same only CPU temperature raised from 38-50°C (60°C+ while gaming) to 70°C+ after few minutes, so I turned CPU settings back to normal. I don't know if the problem is that my CPU is 5year old ( it's the only part in my pc that I haven't upgraded yet) and the thermal paste must be completely decomposed and that I am using CPU stock cooler, but other people who I know got a lot better results. Can you guys please tell me what's wrong or advice me what settings should I use? I am 18 years old and studying at Grammar school so I am not so good at those things, actually I am noob
I am looking forward to your answers. Thanks
( Sorry for my english)

[The Malefic Trou...]

Witcher 3 doesn't use CPU that much but the GPU usage will often reach 100%.

In other words: you're doing everything correctly but unless you overclock your GPU you won't see an increase in performance. Even if so you may expect an increase in frames of 5-10% maximum on stock cooling (well, perhaps 15, but wouldn't count on that).

If you disable NVIDIA hairworks which is a huge resource hog I'm pretty sure the game will run smoothly as hell.

Edit: NVIDIA hairworks pretty much lowers my FPS by 20 even when only enabled for Geralt please disable

There are also some tweaks you may find useful, browse reddit. I gained at least 10 FPS by editing some files in notepad.