Sapphire HD 7970 and i5-3470 Weird FPS Issue

This is a complete specs overview of my current rig:

CPU and Motherboard: i5-3470 Ivy Bridge (Turbo Boost) & Asrock B75 Pro 3M
Ram: G-Skill 4GB x2 (8GB total)
ODD: LG DVD RW
HDD: Hitachi 1TB
GPU:Sapphire Radeon HD 7970 OC Edition 3GB GDDR5 (960mhz/1440mhz)
Case & PSU: Sharkoon T28 Green LED & Seasonic MS2II [Bronze] 650w
OS: Windows 7 Home 64-bit (OEM)
SSD: Intel 520 Series SSD 120GB

Frame rate is occasionally dropping down. And back up. When it is always well good when i had the rig.

CPU Temperature when gaming (Around 65c), while GPU is always at 50 or below.

Can anyone explain what is wrong with the PC? Could it be the parts? I am quite sure about it.

Thankfully, it was built on the 5th this year. I have years of warranty for the CPU, PSU and GPU. I could do a rma.

Looking forward to a helpful reply, and thanks in advance! Have a nice day