will adding a second pair of 2x2gb kit work?

I have asked around on a couple of other forums, but without any satisfying answers. Most tend to agree going for a 2x4gb solution is simpler and safer. Nobody seams to be able to predict what the result of adding a second kit will be. Best I have got so far is that it will work sometimes, sometimes not. I doubt this really is that random. Maybe this is best suited for customer support, but as I bought this computer second hand I am not even sure I am entitled to it.



speccs:



ASUS P8P67 Deluxe, Socket-1155

ATX, P67, DDR3, 3xPCIe(2.0)x16, CFX& SLI, SATA

6Gb/s, USB 3.0, FW, BT, EFI



Intel Core# i7 Quad Processor i7-2600K with Corsair H50 Hydro



Corsair Dominator DHX+ DDR3 1600MHz 4GB

Kit w/2x 2GB XMS3 modules, CL7-8-7-20, for Core

i3/i5/i7, 1.65V, with Connector



Corsair AX 850W PSU



Corsair Graphite 600T



radeon xfx r9 280x



and some random harddrives & original case fans, though I dont see how that could be relevant.





Basically I am not happy with 4gb ram, its just not enough. I am not happy about spending something like 140 USD for similar performance 8gb kit (yes prices are that high here in sweden). If it came to having to buy a 8gb kit I would probably go for some cheaper & lower quality ram.



Seeing as I already have a 2x2gb kit, motherboard appears to have slots for another 2x2, would it not make more sense to buy a second kit?



I would like someone who knows for sure to enlighten me as to what second kit would work. I do not wanna gamble, surely there are some guidelines for this.



If you can suggest a swedish retailer that would be nice aswell, but I can probably manage to find one on my own aswell.