An error detected when overclocking my RAM

I am overclocking my RAM to 3.6GHz. After 2 hours 12 minutes testing with OCCT, I got "error detected". I had this error much faster before the vcore enhance the trial of 1.40 to 1.42. So is it that I can safely increase the voltage of the trial or ACT compared to the current situation? Or do you know what can it come?

Specs
Processor: Intel Core2 Duo E6850 (Aircooling: Noctua NH-u12P heatsink)
RAM: DDR2 PC 6400 3 x 1gb
Motherboard: ASUS P5NE-SLI NB: nforce6
Graphics Card: NVIDIA GeForce 8800GTS 512MB
HDD: Seagate Barracuda 250GB

OC
QDR-FSB: 1596
FSB-ram: 798 or 399
Multi-Coef: 9

Memory timing
399mhz 4-4-4-12-24-2T

Voltage
Vcore: 1.42
Vmemory: 2182
Vnorthbridge: 1208

Temperature (OCCT)
Low: 32 °C
High: 55 °C

Ripple
Vcore: 0.10 (6.38%)
3.3v: 0.02 (0.49)
5v: 0.03 (0.55)
12v: 0 (not moving)

Could you tell us little about cpu vcore, I mean you risk nothing with 1.45v cpu?

What values do I trust? Those that are returned in bios or those indicated by OCCT. Because with a value of 1.42 to vcore, OCCT shows me that the vcore is 1.50. When I mounted the vcore in bios at 1.45, the vcore is 1.52 OCCT software tells me?

Mine is at 3.8GHz, I am having Vcore of 1.30 and 1.28 in BIOS under OCCT, so a Vcore of 1.45 to 3.6Ghz, it is totally useless!

Meet your Vcore at 1.30V and after that you meet PLL Voltage 1.50. And everything else you increase +0.10 V except the PCI-E need a 1.50V.

Thank you Nihir for your response, however overclocking two identical processors is not same with the same values.

Moreover, the PLL voltage is not present in the BIOS settings of my motherboard.