Need help with additional RAM for rig

[SpittingLlama]

Hi all!

I'm here with some questions about memory.

 

Specs:
i7-920 @ 2.6Ghz  OC@3.8Ghz  http://ark.intel.com/nl/products/37147/
Gigabyte GA-X58-UD5 rev.1 (latest bios)

3* 2 GB DDR3 12800 8-8-8 @ 1.65 (OCZ3G1600LV6GK)    http://www.newegg.com/Product/Product.aspx?Item=N82E16820227365

MSI Geforce GTX 770 Lightning (stock speed atm)
Samsung 840 Pro 256 Gb (ssd) + 2x Samsung spinpoint 1TB 7200RPM in raid 0
Windows 7
 

Problem: Not enouph RAM for what I'm doing atm (gaming mostly, programming, photo editing and 3D rendering) Hitting the 5.5GB mark while playing BF4 and getting framedrops from it. Also impossible to turn on shadowplay because of it. (fresh windows 7 install btw)

Asking: So this CPU and MOBO use triple channel (2x 3slots) and is also limited by the bus frequency of the CPU (stock 1033 mhz with OC at 1200mhz)
Should I buy extra RAM to put with the ones I already have in this rig or just buy new RAM and keep the ones I have as spares. The thing is that I can't find triple channel RAM anymore, it's either Dual or Quad. Finding matching CAS latency and voltage is also not that easy.
Should I try and fill all channels for better performance? I'm also planning to upgrade my MOBO in about 8 - 12 months. So should I buy with an eye on the future?

Any suggestions?
How much RAM should I need these days? What latency's should I look for?

Much appreciation for reading my ramblings!
 

SpittingLlama
 

[ERSCreeper]

http://pcpartpicker.com/p/akT

[Sharif]

if you want to fill it get 1 dual ram and 1 single ram from the same model and for these days you need about 8gb ram

 

if i were you i would change all of them together plus there might some problem with compatibility issue if you try to use that with the new ones

[SpittingLlama]

thanks for the reply's

[LogicalDrm]

I vouch for getting another 3x2gb kit if you can find any.