My core speed and multiplier are dropping suddenly during a stress test.

[Pikmonste]

I'm completely new to the whole overclocking scene, and I'm trying to squeeze some power out of my FX-6300 here that I'm rocking. After tweaking with settings in BIOS, I managed to get my PC to not BSOD after a second of Prime95 by increasing my voltage. Currently I'm hitting 4 ghz at 45* C, and I was happy until I noticed something: it usually stays at 4000 mhz, but every few seconds it switches to 3000 mhz suddenly. I did some googling, and I disabled CoolNQuiet, and I'm lost. What could be causing this?
Images:

every few seconds:

 

[geofelt]

FX-6300 runs hot; likely your temperatures are getting too high and the processor is throttling.

 

[maxwellmelon]

your CPU temp looks good to me (i have fx 8350 oc to 4.8ghz) but it is still better to use amd overdrive to check cpu temps then other programs on the fx. more on that http://www.tomshardware.com/faq/id-2122665/understanding-temperature-amd-cpus-apus.html

as long as your "thermal margin" is not a 0 or negative number then your cpu should not be throttling on its internal protections though its best to stay at 10c or higher. (0 is where throttling begins)

I'm more interested in what motherboard you have? Lower end boards with small heat sinks on the voltage regulators can cause this from the voltage regulators overheating and then triggering protection. I actually had to install a small fan (from a 486 cpu) to keep my regulators cool to allow my cpu to over clock due to water cooling on my cpu (less air flow over the VR) and I have what is considered to be an ok motherboard for the 8350 overclocking.