GPU limiting factors

[gamerxxl12]

Frist time poster, but avid tech lover

I'm planning on building a new computer some time this summer and I need to find the parts. Then the GTX 770's came out I was looking through them and saw that Gigabyte's cards could be sold as 2Gb, 384 bit or 4Gb, 384bit. I am planning on using 2, 1080p, 24" monitors, while gaming on one and having something like Skype open on the other.

My question is, should I get the basic card with 2Gb and 256 bit or getting the Gigabyte 2 or 4Gb version with 384 bit?

Also in theses situation what are the real limiting factors?

-Thanks

[Hyydrah]

The 2GB card should be adequate since you'd only be gaming on one 1080p monitor. What do you mean by limiting factor, a bottleneck?

[ERSCreeper]

I would settle on the 4Gb since most current games use at least 1.6Gb of Vram, so with upcoming games 4Gb would be a better bet.

[gamerxxl12]

Yes a bottle neck, I was worried that 256 but wasn't going to be enough for 2 monitors while gaming.

Can anyone tell me about Gigabyte's cards, they look like they would be loud.