GTX 680 , Time to upgrade?

Hi....

I'm getting the urges those days to either jump to gtx 980 or SLI my 680 , since I'm not sure what I'm missing by staying at the current setup, I can't decide if I will gain much from such an upgrade?

I'm using single monitor setting at 1920x1080 (HDMI) , I always go for the highest gfx settings, most games are working without noticeable sluggish.... I do face some discomfort and some nausea after playing games like dying light (maybe the refresh rate @ 60 hz is the reason or FPS, I'm getting 48 FPS on that game )

I'm looking for factors like: future nvidia plans for new generations and better upgrading opportunities , how much performance gain should I expect , are there stronger factors can help reduce the effect of discomfort/nausea other than the gfx \fps rate ?

Here's the kind of gains you can expect:
http://anandtech.com/bench/product/1348?vs=1351

Not sure about the nausea, could it be motion blur doing it?

You're probably too close to the monitor when you feel nausea, back off!!!

I'm at least 7 feet away from the monitor (40 inch) ... Not sure what causes it , but I feel the need to sleep after playing for 1hour or less sometimes for it to go away , it might be because of sudden turns in the game and yeah that might include some blurring effects that don't help the situation... its frustrating as I want to play the game while I don't want to waste my day sleeping to lay the effects of nausea of me.

So in regards of performance gains, some games show significant increase in the bench marking compared to the 980... I couldn't find 680 SLI option, not to mention that mostly these comparisons are done using 2 GB cards, while I would SLI 2x4GBs

Performance will be about the same with 2x 680 and 1x 980, but the 980 does still have the advantage of lower power.

vRAM doesn't directly impact performance, so 2GB vs 4GB on the benchmarks will be nearly identical.
The advantage of more vRAM is the larger frame buffer. It helps prevent textures popping in/out.

Did you try turning off motion blur??

I haven't tried a full hour game yet, but yeah its definitely better when I turn off the motion blur. strange, this didn't happen to me before, I tried GTA V today and it has the same effect...

I cannot play games with motion blur off, I find it just makes the experience worse and can make me dizzy. I upgraded from a 680 to 980 when they came out and feel that newer games definitely feel a lot smoother, although I did only have the 2GB VRAM 680 (so memory capacity may have been limiting performance in some situations).

No ones brought up budget, as in what is yours?

Just getting another 680 is vastly cheaper than one 980 for roughly the same performance, however the SLI setup will be much less efficient if you care about that kind of stuff.

As for your motion sickness it's something that will go away with time, you have to train your body out of it.

What it is, is your visual references to motion conflicting with your semicircular canals in your ear, once your body learns to dissociate the two it goes away pretty much entirely regardless of what image is displayed infront of you.

When I made the move to a 70 inch it took a minute to get used to it again because more of my field of view was occupied by screen space so there was less peripheral vision cues to anchor my point of reference for balance.

EDIT:
P.S. If you think getting dizzy looking at a screen is bad, just wait until you start playing on an Oculus or similar, both amazing and horrible at the same time. The disorientation is so strong that some people vomit.