Hi I am planning an ultrawide build with the 21:9 Acer Predator X34A 34" 3440x1440 100hz g-sync monitor.

I am finding it hard to figure out how much FPS improvement SLi 1080's would be over just one 1080.

All the benchmarks I can find comparing one 1080 to SLi 1080's seem to focus on 2560x1440 and 4K.
CPU will be: i7-6850K

Also, a video I watched said the 1080 SLi performance should improve over time with drivers and game development.

Could anyone give me advice here?

I'd be happy to sell 1080('s) and upgrade to 1080ti in ~Q4 when they come out, but don't want to drop £650 more now for second 1080 if it's not really going to be worth it.

Ultrawide 1440p performance would be somewhere inbetween. But if the games you play support Sli then you would reap the benefits. But if the games you play aren't supported, then the 2nd gpu would be a paperweight, and you'd be losing value for no benefit.
Go with one 1080 to begin with, because if the games you play dont hit the frames you want, GSync will make them at least playable.

Currently using triple 1080s (well 3rd is just Phsyx) and a pair do a cracking job in most titles that support sli fairly well. Using the PG348Q which is similar to the x34A so would work very nicely. Having said that even a single 1080 does a cracking job while the second does allow you to notch up the eye candy in heavy titles such as witcher 3.

I would however agree with the above advise, go single 1080 and see how it pans out for you. If it quiet the experience your after and the titles you play often support SLI then look at a second one.

I used SLI 980 Tis for a long time at 3440x1440. Very good performance boost in titles that support SLI well, such as The Witcher 3 and Dragon Age Inquisition. However, there are quite a number of games that don't support SLI as well as they should. Therefore, from a value standpoint, SLI is poor. But your overall gaming experience will definitely be better with the power of two cards over one, especially with a 100 hz panel.

I have personally settled for a single 1080, and will probably buy the 1080 Ti when it comes out.

nightwork said:

Could anyone give me advice here?

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Or you could do the same as what am doing...

Buy one GTX 1080 and try it and if your not happy with the performance you get from a single GTX 1080 at 3440x1440 then buy another one for SLI...

I remember last i was using SLI back in the 560 ti days if SLI wasnt supported properly i just turned the second into the anti aliasing monster. I dont know if nvidia still supports this but back then you could let the second card handle anti aliasing and use crazy numbers.. worked great with games like world of warcraft back then.

Wow thank you all for your enlightening replies, interesting stuff.

I think i'll take the consensus of advice and stick with one GTX 1080 to start with; as it seems to be really dependant on the games etc. No harm in adding one later as you say (or maybe a Ti by that time).

Much appreciated.

Same I have a pg348q and 1080 SLI is perfect for it. Havent had many games so far that have struggled to hold 100fps with ultra settings. The vast majority of games support SLI well.

It's also likely the Ti will be out next year. The Titan might make an appearance Q4 but that's going to be no way cheap.

The truth be told, the 1080 is a 3440x1440 card not a 4K card as it has been touted by many, so you should do reasonably well on the single 1080, but not to the levels of your monitor if you like Eyecandy and latest AAA titles.

As others have said - there's no rush. Try it with one and if its not enough, add another.

Radox-0 said:

Currently using triple 1080s (well 3rd is just Phsyx) and a pair do a cracking job in most titles that support sli fairly well. Using the PG348Q which is similar to the x34A so would work very nicely. Having said that even a single 1080 does a cracking job while the second does allow you to notch up the eye candy in heavy titles such as witcher 3.

I would however agree with the above advise, go single 1080 and see how it pans out for you. If it quiet the experience your after and the titles you play often support SLI then look at a second one.

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Sounds like a seriously nice albeit a seriously expensive rig. Is it solely for gaming out of interest?

I'm considering getting 1070sli for 3440x1440 so I'm hoping it's enough.

bakes0310 said:

I'm considering getting 1070sli for 3440x1440 so I'm hoping it's enough.

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2 x 1070 will be fine. It roughly equates to 1.5 GTX1080s, so you'll be fine.

Its one of those things. 1 isn't quite enough, 2 is a bit overkill for MOST titles, depends on target FR though.

In fact, I'd say a 1080 + 1070 would be the best cost / performance if it were possible

Go with single for the time being. SLI needs a shot in the arm after the last year or so, so you'd have to go into it with your eyes wide open, especially around support of which games you want to play.
A single 1080 manages most 3440x1440 stuff well, but there are instances where you'd hope for a little bit more.....primarily in the minimum frame rate areas, but nothing too major and certainly nothing that a small drop in detail can't sort out.
As long as your not aiming for constant 100fps it's more than fine.

Just added a second TX for 3440x1440 and Ive been very pleased so far. The new games Ive played have worked well (mirrors edge,total war,fallout 4 dlc) and the older ones have been optimised now like the witcher 3.

Is it needed? Its up to the user at the end of the day but its nice to turn everything up and not have to tweak anything

Seeing i was using one 970 for about a year with 3440x1440 (of course medium to high settings) i was getting excellent performance.

now im on a gainward 1080 GLH it handles with with absolute ease, and everything on ultra.

Radox-0 said:

Currently using triple 1080s (well 3rd is just Phsyx) and a pair do a cracking job in most titles that support sli fairly well. Using the PG348Q which is similar to the x34A so would work very nicely. Having said that even a single 1080 does a cracking job while the second does allow you to notch up the eye candy in heavy titles such as witcher 3.

I would however agree with the above advise, go single 1080 and see how it pans out for you. If it quiet the experience your after and the titles you play often support SLI then look at a second one.

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You have a 1080 just for phsyx??

subbytna said:

You have a 1080 just for phsyx??

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Third was a gift from GF, she does not know what I buy (thankfully) so picked my up a GTX 1080. Kind of pointless and definately would have returned it, but do miss the way prior Tri-SLI looked so meh, ended up keeping it.

I'd stick with one for now then move to Ti once it's out. It should be the perfect card for single gpu and 1440p ultrawide plus the eye candy and 60fps+ The 1080 being better suited to standard 1440p

I have a 1080 fe coupled with a 6700k powering an x34 at 95hz. I only ever get to play rainbow six siege, bf4 and swbf. With rss at medium settings and no msaa I get 75fps on average. The others I get a permanent 95fps at ultra all the time.

I very much want to get a second card but there would be no real benefit at the moment. Rss barely supports sli and bf4/swbf are already maxed with a single card.