RAM addition to a Gigabyte GA-H55-U2DH v1.3 motherboard

[radudh]

Processor is Intel i3-560 3.33GHz.
Current RAM is Kingston 2x2GB DDR3 HyperX Blu CL9 1600MHz 1.65V (code KHX1600C9AD3B1K2/4G).

The memory is currently working at 1333MHz and 1.5V (it's in the auto setting, I didn't change anything in BIOS).

I intend to add new RAM to the system and I can choose between:
- Corsair 2x2GB, DDR3, 1333MHz, CL9, 1.5V - code CMX2GX3M1A1333C9
- Corsair 2x2GB, DDR3, 1600MHz, CL9, 1.65V - code CMX4GX3M2A1600C9

Which one has the biggest chances of working in my system?

PS. I just want to add that I don't need to OC, I'm perfectly fine with memory working at 1333MHz and 1.5V

 

[julienruc]

If possible, it's best to use the same RAM sticks. If you can't then you should add sticks with the same frequency and with the most similar timings because your motherboard will automatically use the slower timings for both RAM types.

Also, note thay if you have 1666Mhz. Might as well overclock it as your wasting speed.

They're lifetime warranty so it's 100% safe.