GTX 970 or GTX 980

The 970 gives incredible bang for your buck, much more so than the 980. If you don't want to spend $550 on a GPU the 970 is a fantastic choice.
That extra $250 gives you 10-20% more performance, according to benchmarks.

The 970 screams value when looking at the price to performance. Unless money isn't an issue, I advise against having THE top card.

That's more of a personal preference than anything.

GTX 970 is good for 1080P and 1440P or 1080P surround gaming at ultra (1080P) or medium-highsh settings at 1440P and surround.

GTX 980 is good for 1080P surround, 1440P surround or 4k gaming.

So if you have a lower res monitor then the 970 is better.

well if youre using a 1080p monitor
go for the 970
the 980 is overkill
hell even the 970 is overkill
and the 970 is slower than the 980
but not so much as to justify the price difference
the performance difference between the two is more evident at higher resolution i.e. 1440p 4K

It depends on the games you want to run, the resolution, and your budget. The 970 is 85% of the performance of the 980 for 65% of the cost.

So what games will you be playing and at what resolution? Also, what is your current computer and what is your budget.

I bought a 1440p monitor so i grabbed two 970`s at the same time.

Wait, you have 2 770s?
A single 970 or 980 isn't going to be an improvement, the 770s outperform both cards.

At 1080p that's enough for almost all games. A few games, like Watch Dogs for example, may benefit from more VRAM but overall your going to see a loss of performance if you replace the 770s with a 970 or a 980. A true upgrade would be 2 970s (or if you're rolling in money 2 980s). Otherwise I wouldn't bother.

If you have 2 gtx 770's then wait till the next 20nm release from Nvidia.

To be totally honest, I would consider waiting for the 20nm cards by AMD. Their R9 390/X is going to be insane and certainly something to look out for.

simple answer ... if the 970 is only a little less of performance for half the price, buy 2 and sli them

Go for the 970 mate. And later you can buy another 970 card. This way its much better.

I'd like to extend the OP question further, using this thread if I may.

Along the same lines as he asked, but I cannot find any technical answers to this question which I have in 2 parts:

I understand that both the 970 and 980 cards can run a single 1440p monitor just fine.

1) What happens to the demand on the card (either 970 and 980) if you add a 2nd monitor which is a 1080p?

2) What happens when you add a 2nd monitor of the same 1440p type?

Does the 2nd monitor of 1440p place twice the demand on the existing card, or is there some other type of algorithm curve used to describe the single card handling the imagery going to 2 different screens?

Personally, I would be using both screen to have additional open windows for working, but regardless, I just wonder how a 2nd monitor affects the single card.

I have been in the streaming network on Twitch for a while, and I'm glad to answer your questions in my experiences or the experiences of other streamers. As a GTX 970 user I would be delighted to share you my experience on the amazing graphic cards, but from all the answers above I guess you would had a little bit knowledge about the differences between the GTX 970 and GTX 980.

But for field performance, the GTX 970 is a mid-high tier graphic card that is capable of the most high-end gaming requirements on modern market. For now the GTX 970 is sufficient for almost anything and basically anything above it (namely the GTX 980) is just an over-killing machine for graphics designer or any specialist working on a field that really requires on that edge of performance.

Now for the dual monitoring question, the answer relies on what you're going to do with those monitors. The requirements for a graphic card depends on the program you're using, therefore if you're going to game on one monitor and just gonna surfs the internet on the second one, the extra work for the second monitor should not be concerned. Having one program on several screen would require less work that having several program open at once, and usually a single 980 would be sufficient if you decides to split-screening a game into two or three.

Also, according to TotalBiscuit, a renowned critic on youtube that made videos about games, even two GTX 980 couldn't handle the latest Assassin Creed game in the highest graphic setting. The fact that the graphics in Assassin Creed was not that amazing at all but the hardware requirements for the game was among one of the most ridiculous had shock TotalBiscuit quite a bit, but this is the result from UBI for not optimizing the game on PC at all.
Therefore shall you decides to wield more than one graphic card on your machine, remember that running a program is not always about how much money you could throw into the pit, but rather the program itself as it's currently not optimize for the model of the graphic cards you're using, or in most of the cases, were not capable of the second graphic card.

For my opinion, I would say stick with one GTX980 and just over-clock it if needed.
According to my own observation on how the computer industry goes, the market tend to favor those who weld one high-end performance graphic card and dual graphic cards is not yet an efficient method on boosting your computer's performance. By 2014, the old method of over-clocking your graphic cards is still by far the most efficient and most friendly way to increase graphic performance.

monitor can be upscale