Alrighty, I'm slowly gathering up some funds to upgrade.
Right now I'm running 4gb (2x2gb) DDR3, i5-3570 CPU, 64-bit Win7 and Two Radeon HD4870 512mb versions in Cross-fire, Mobo Giga-Byte GA-B75M-D3H.
Sometime mid 2014 I'll be grabbing a R9 270X or 280 once funds allow.

Right now I'm looking at RAM as it's largely cheaper than a new GPU.

I've currently got LINK.
And I'm wanting to upgrade to 8gb+

So I can either buy an identical set and run 4x2gb sticks, or I can grab a 2x4gb kit + my current and be sitting at 12gb.

The 2x4gb kit is LINK

They seem to have the same timings/frequency and such, so I'm wondering if I'd run into a problem trying to use them together.

What do you guys suggest?
Or maybe get a new GPU then RAM, or just scrap the entire system and build a new one.

Also. Don't mind the shocking prices & terrible websites, that's New Zealand for you.
I wish Newegg shipped to NZ.