I have notice random reboot at time, (gaming or just using the desktop). this mainly accrues when i set my ram @ 1866mhz 9-10-9-27 1.5 which the ram manufacture recommends. this problem only started a few days ago, i haven't notice nay problem when i set my ram, to auto settings in bios which defaults it to 1600mhz 9-9-9-24 1.5.
I have also ran 10 passes of windows memory diagnostics tool and it gave me some error.
Is my ram bad or it just need more volts or betting timings?
It sounds like it's slightly defective and can't run at its full rated speed at default voltage. I'd try bumping the voltage slightly if your bios supports that then run your memory diagnostics tool again to see if it's more stable. If not, I'd either return it and get a different model or just except the slight performance loss and run it at the slightly slower auto settings.