I've been experiencing some issues such as getting the blue screen and my computer crashing after adding 4GB more ram. I currently have 2x2GB ram sticks, I have recently added 1x4GB ram stick. I'm wondering if the ram doesn't work together correctly, or there is something that I can change in the BIOS that will fix my problem.
Are you sure it's that RAM? Honestly anything over 1.6v can be a problem and anything over 1.65v can damage your CPU. Intel says anything over 1.5v voids your CPU warranty. If you are really running 1.85-1.9v RAM I would go smack whoever built your computer and hope to hell your CPU does not die soon. Seriously whoever did that is an idiot.
I truly am amazed your computer would even boot with RAM voltage that high. Especially with a P67 board.
That's better. That is still a 6GB kit though not 4GB so I doubt that's exactly it either.
Either way I doubt it's going to work with the PNY. Not only can mixing brands cause problems you still have different voltages and speeds. The PNY does not bother listing timings or even a part number to look up the timings.
It may run together at 1.5v DDR3 1333 cas 9-9-9-24 2T.
One other thing you said. You have a Sandy Bridge system with RAM at 1666? The only way to run "outside" a standard speed ( 1333, 1600, 1866 ect. ) with a Sandy Bridge system is to have an overclock via the BCLK. This is dangerous as it overclocks everything, meaning hard drives, the PCI-E slot the RAM....basically everything including things not designed to overclock like your hard drives. This can cause data corruption and even kill parts. Since you only have a 66Mhz RAM overclock I assume that the BCLK is not overclocked much but the safest value for it is 100.