3840x1024 Eyefinity. 2GB GPU a must? Advice please.

[uruloki43]

I'm looking at building an approx $600 gaming PC in the near future. I already have 3 1280x1024 monitors and plan on playing games of the caliber of StarCraft 2 (Eyefinity not supported), Diablo 3 (officially not supported though available in beta), and Guild Wars 2 (officially supported to my knowledge); as well as possibly dabble in Skyrim and Tribes: Ascend.

As of right now, my wish list is leaning towards an i3-2120 ($110) and a HD 6950 2GB ($190) system.

My question is when using Eyefinity, how much of a boost in performance will I see from using a 2GB GPU as opposed to a 1GB card such as a HD 6850 ($120)? Would it be worth the extra money or should that be invested in a better CPU such as a i5-2400 or i5-2500k ($200)?

So i3-2120 with a HD 6950 for the few games that support Eyefinity?
or a i5-2500k with a HD 6850 for processor heavy games like SC2 and large scale WvWvW battles in GW2?
or save a buck and just get i3-2100 with a HD 6850 for a more balanced system and consider Eyefinity more of a perk and not build my system around it? The extra $80 and under $500 total would be very nice.

And finally, what exactly does the extra RAM in the GPU help with (ie: HD 6870 1GB v 2GB)? I've read that it is only beneficial when using AA on the largest screen resolutions and would therefore be useless on games limited to one 1080 screen. Is that true?

Thanks for any input!

 

[uruloki43]

I have a follow up question:

How does the processor's impact on performance scale with screen size? In both of the Eyefinity focused set-ups you recommend, the CPU is a i5-2500k.

Any particular reason for this?

Is an i3-2120 simply too weak to handle such a high resolution at high-ish (not ultra) settings?

I understand that paying almost double for a better processor is going to yield much better performance and that the i5-2500k can be OC'd on top of that and therefore it will last me longer into the future... but is there something else I'm missing that the i5-2500k offers for Eyefinity?

Thanks again for your input, you answered my curiosities perfectly.

 

[uruloki43]

Best answer selected by uruloki43.

 

[uruloki43]

Duly noted and thanks for the clarification.

I especially agree with impact SC2 has on the CPU. Stupid Day[9]'s monobattles.

Ideally I'd just get it all, but I want to feel somewhat fiscally responsible and try to cut back as much fat as possible unless I can reasonably justify it, such as the 2500k for SC2 and/or a 6950 for Eyefinity. But in the end, $100 isn't much more than an extra day of work for compounded returns on my investment.

Thanks again for your input.