Overclocking with two different sets of ram (8GB total)?

[FrozenDevl]

When I first built the pc I intended on OC'ing it but never got around to it since my temperature was very high, so move forward a year and I ended up buying new ram. Then just a few days ago I also bought a better heatsink and my temps have gone down enough in my opinion to try to overclock. The question (problem?) is that I have two different sets of ram, so what timings should I use? Should I use 5-5-5-15 since both sets have that even though the MHz would differ? Any advice is helpful, thanks in advance.
I've attached a pic of what I'm running instead of listing everything:

 

[sirmonkey1985]

by default it will use the slowest sticks ram speed so 6-6-6-18.. doubt the kingston will run at 5-5-5-15.. im guessing its generic kingston ram with no heat spreaders on them? if so then even raising the voltage to get faster timings will not work and will most likely result in dead sticks by the end of the week..