GTX 680 2GB or GTX 680 4GB

[joshua_jc08]

In this review it says ASUS GTX 680 2GB Direct CU II TOP beats Palit Geforce GTX 680 4GB for about 2 to 5 frames.
http://www.guru3d.com/article/palit-geforce-gtx-680-4gb-jetstream-review/21

I'm planning to have a 2 to 3 monitor setup, I'll be using it for extreme gaming and video editing/encoding. Please help and I'm not going to S.L.I.

Also kindly suggest me a better Power Supply (PSU) as I'm having this specs as my first gaming pc:

Mobo: Asus Maximus V Formula or Gene
GPU: Asus GTX 680 2GB DC2T or Palit GTX 680 Jetstream 4GB
CPU: i7 3770K
Monitor: HP x2301 x 3
SSD: Intel 520 series or OCZ Vertex 4 series

 

[xtreme5]

this because of games does not require more than 2gb of vram, 4gb is overkill for games.