Are these memory timings causing crashes and bsod?

[diddz]

I have 2x2gb memory sticks running dual channel.i had 2gb and bought another 2 gb a couple of months later from the same shop.All the specs are the same apart from the Supported Module Timing at 533.3 MHz.
One stick has 7-7-7-20 and the other is 8-8-8-20.
Could this be causing freezing on start up and bsods?
I have an asrock n68c-s ucc and im using ddr3 Memory Speed: 666.7 MHz (PC3-10600)
and im using HWINFO32 for my info.
Also i have never been able to overclock this,even from new.could that be because of the timings?

 

[Layback Bear]

This might help. Match ram means matched. Ram to work properly need to be match. Different speed ram and different settings is not matched.
First thing you have to know what you mother board requires and then what your cpu requires.
ASRock > N68C-S UCC
-----------------
*DDR3 and DDR2 are supported separately.

**DDR3 memory is only supported by installing AM3 CPU.

***Due to the operating system limitation, the actual memory size may be less than 4GB for the reservation for system usage under Windows® 32-bit OS. For Windows® 64-bit OS with 64-bit CPU, there is no such limitation.

****Support with AM3 / AM2+ CPU.
---------------------
AMD Athlon II X4 640 Processor Specifications & Features

You can do a little Google Home Work and find more information.