Does voltage indicate CPU overclock throttling?

[MyKeyblader]

I have a lowend ASUS board, the m5a 78l-m. It is a 4 phase board and doesn't have VRM cooling. My fx-6300 runs at 3.5GHz stock, but I overclocked it to 3.9GHz at STOCK VOLTAGES. I don't know what the actual voltage is, and if I wanted to increase it I wouldn't know to at what level to increase it to, so if anyone can answer that too I would really appreciate. But anyways, I monitored the voltage using CPUz and AIDA 64's stress test. At idle it runs at 1.200 volts, but when stressed it goes down to 1.188 volts. Does this mean the VRMs are being throttled because of my minor overclock?

 

[Justiceinacan]

I dunno if that motherboard has a temp sensor for VRM's, but try HWmonitor and see if they're getting hot.