HELP Please with my delimma - Upgrade versus New

I currently have the following system:

Alienware Aurora:
*Integrated PWA 875 (is that the PSU)
*Heatsink, Liquid Coolding, CPU, ASETEK
*Dual In-Line Memory Module 1G 1333, 128 x 64, 8, 240, 1RX8 (I've since added to 3gb)
*Dual Graphics card; AMD 5670, M206
*Upgraded hard drive to a 1TB Western Digital Black a couple years ago
*i7-980X, 3.33, 12MB, GFT, B1 (unsure what GFT, B1 means)
*Currently have 0.99 RAM left for useage

The useage is typical comp stuff plus gaming. Games I've been playing are:
*Arma II and Arma II Dayz Mod
*Dayz Standalone
*Far Cry
*Borderlands 2
*And a few other games my mate and i play
*Minecraft (son plays)
*Warcraft III (I know, outdated, but i still mud too! - Arctic mud)

Your advice would be most appreciated.

Dayz runs laggy (both mod and standalone) with all settings set very low and all background applications shut down (no steam, dayz commander, skype, etc).

What should I do?

Warm Regards

I agree with holeyguy66 the ram need to increase to 8 gigs for sure. Your I7 980x is still a beast and is being throttled by the ram and the 5670..Increase the ram put in a modern gpu like a 760 or 780 and it will scream.
And Welcome to the Forum, your not far from me I use to live in Carlsbad
Thank you

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I bought a triple (3x4mb) ram set from Corsair with fan, and a gtx690 graphics card (unused open box :) ) and now everythin is running killer. All settings at max with ZERO lag, blur etc.

Ya'll saved me at least a grand.

Again, thank you.

For those that are considering doing what i did, the older R1 Aurora Alienware has an extra connection for a cpu/system fan. This is a 4 pin connection, and the Corsair Vengence fan has a 3 pin connection. You simply plug the 3 pin in the 4 pin connection and works perfectly. One of the pins is slightly offset for this specific application.

Also, the GTX690, and probably others, has two 4 hole/pin input for power. My R1 has 2 sets of power wires that are 3 (male) plus a single (male) attached to the same bundle of wires. You use the 3+1 to power up the card. It only works one way and you will see how when you do it.

Hope this helps for those of you like me, ignorant.

Warm Regards