Adding some memory to my (relatively) old Kingston sticks

[Punterooo]

Hello,
I would appreciate a piece of advice about expanding my RAM capacity. Here's what I've already got:

MB: Asus P8Z77-M with total 4 RAM slots
Installed RAM: Kingston DDR3-1600 PC3-12800 (2x 4 GB)

And, in case it matters somehow:
CPU: i5-3570K
GPU: GTX970

So I have two free slots in my MB and the plan is to buy 2 more 4 GB sticks, the question is how to choose them wisely for good compatibility.

I'm sorry if this question sounds silly, I'm not an expert in hardware.
Thanks in advance!

 

[Tradesman1]

Not silly at all, more people should ask Thing is there are no guarantees when mixing packages of DRAM - even if the packages are the same exact model of DRAM. Best to get a single package of the full amount you want, that way all sticks have been tested to play nice and are guaranteed to play. See more in my Fiction article, items 2 and 6 here:

http://www.tomshardware.com/reviews/ddr-dram-myths,4155.html

 

[Punterooo]

Not silly at all, more people should ask Thing is there are no guarantees when mixing packages of DRAM - even if the packages are the same exact model of DRAM. Best to get a single package of the full amount you want, that way all sticks have been tested to play nice and are guaranteed to play. See more in my Fiction article, items 2 and 6 here:

http://www.tomshardware.com/reviews/ddr-dram-myths,4155.html

Thanks for quick reply and for such an informative article!
So it seems like the most safe option is to buy brand new full 16 GB package, but still, is there any criteria I may be looking for that can help me get as close as possible, or is the behavior of memory sticks from different packages totally random and unpredictable?

 

[Tradesman1]

Are you OCing the 3570K - if so could go 2133 or so. Otherwise would stick to 1600. If thinking about possibly mixing would look for same data rate, timings and voltage as the old....and give them a try. If problems, give me a shout and we can try voltage/timing adjustments to try and get them to play

 

[Punterooo]

So I just bought another similar 8 GB stick of the same manufacturer, with the same clock and that PC-something number, and after some playing around (placing the new and the old sticks in different combinations; undoing all the overclocks, re-X.M.P.-ing and redoing the overclock) all worked out just fine. Maybe I should consider myself lucky this time.

Thanks Tradesman1, your tips were helpful and quite educative.

 

[Tradesman1]

Glad all is well