Lag spikes during gaming

[Envious]

Hi there, I have been having trouble with my PC lately. (specs below)
during games I will be at say 300FPS and then suddenly it will drop to 50ish fps for 1 second then shoot back up to 300fps again. this happens in most of my games but CS:GO is hit the most, call of duty titles that I play aren't too badly affected
♠Nvidia Max performance settings (no power consumption protection)
♠AMD Cool n quiet disabled


♠SPECS

- MSI 970 Gaming Motherboard AM3+
- AMD FX-8350 @ 4.20 GHz
- GTX 750ti (Asus 2GB)
- OCz Agility 3 240GB SSD (Boot)
- WD 1TB HDD BLUE 7200RPM
- Seagate 5400RPM Drive 500GB
- G-Skill Rip Jaws @ 2133MHz
- Zalman Z9+ Case
- Corsair CX500W
- Windows 7 64 Bit

My windows 7 install is 3 weeks old with all updates installed, and it's legit. I had this problem before and it was my PSU which I got changed and now it's kind of coming back.

 

[GokAy]

Disable C1E in BIOS too if enabled.

Try a clean startup - http://www.sevenforums.com/tutorial...ation-conflicts-performing-clean-startup.html

Are you on a High Performance power plan? (Control Panel - Power Options)