SLI- 60 hz monitor- Worth it? Should i attempt to upgrade?

What is the rest of your build? Your motherboard or power supply may not be enough for SLI, and then in order to upgrade those, it would be more cost efficient to just get a 770 or 780. As for your issue, that is exactly what G-Sync is for.

Basically this. It would be better to run a single 780 over two 760s. And I don't believe a 760 even in SLI will be a constant 100+ fps in BF4. It will certainly be 60+ a lot of the time, however. Here's a video here showing dual 760s in BF4. https://www.youtube.com/watch?v=urQ_iOW4hTY

With standard v-sync on, if your GPUs can't hold frame rates at 60, it will drop your frame rate down to 30 to maintain a constant rate until the GPUs can output 60 again. When it drops to 30, things can get choppy. Adaptive v-sync is better because it will hold your frame rates at 60, but if your GPUs can't deliver at 60fps, v-sync shuts off and the cards run at whatever sub-60 fps rate they run at (ie 52). In either case, when v-sync is on, it introduces input lag to the mix throwing off the timing between your mouse clicks and what you see on screen.

I would recommend to anyone with a capable video setup to go for a 120+Hz monitor (in this case a 144Hz). They are great because the perceivable tearing is minimized, there is little input lag, and fast refresh rates facilitate little blur.

Although, something to consider is the G-sync monitors that will (possibly) be released sometime this quarter (April-June?). They are monitors with variable refresh rates to match the video card's frame rate. No tearing, no input lag. Also, they will have 1ms response times so there will be no noticeable blur. I'm actually waiting to upgrade my own monitor to the upcoming 27" Asus ROG 2560x1440 144Hz G-sync monitor.

Well, everything should support SLI, so you're good there. Temperatures should be alright. If it's within your budget, an upgrade to a 144hz monitor wouldn't hurt at all, not only will you not have screen tearing, but you'll also have a 144hz monitor. That's probably your best option, really.

Any 760 configuration performing better than a Titan just isn't physically possible. It's always best to go for the best single card set up you can afford, because a single card will always outperform an equivalent SLI set up, and as good as dual 760s can be, they're still not even close to equivalent to a single Titan, or even a 780 Ti (The Ti is better than the Titan for gaming anyway) two 760s is closer to a single 780 than anything.

You start with the best GPU within your budget, then you SLI when necessary. This allows you to skip buying a higher-priced card of the newest gen while gaining performance over the single higher-priced card. This way, you can avoid the higher price tag for a gen or two.

Here's an older comparison of 760s in SLI versus 780s:
http://www.tomshardware.com/reviews/geforce-gtx-760-vs-780-sli,3686.html

Agreed. It makes sense for you to pick up another 760 and skip, at least, the next gen of video cards.

I would proceed as planned. The only way I'd replace the 760 would be to wait for the next gen or another two gens from now.

Also, that's a decent OC on the 950 and good max temp. If you know how much Wattage the GPU requires, you might be able to determine whether or not you need another PSU or not. Each SC 760 uses around 170W:
http://www.guru3d.com/articles_pages/geforce_gtx_760_evga_superclocked_acx_review,5.html

Two would require around 340W and your OC'd CPU might require 230W? Check the CPU wattage using your favorite tool and see what it requires. That XFX power supply is made by Seasonic (in my opinion they make the best PSUs available).

With one 770 in BF4 I get better performance in BF4 than that one video I linked earlier where the guy had the two 760s (was typically in the 80s for fps, while occasionally dropping into the high 50s during a big explosion or something), with two 770s it was always 100+ fps. Testing SLI for the first time on one map in the same spot I went from 84 fps to 125 instantly, just by putting in a second 770, and both the before and after fps numbers are with everything at max settings at 1080p (except resolution scale, that's still at 100%). All that said, if you already have the 760, it may not be worth it for you to go dropping that kind of money, especially when a single 780 or 780 Ti would still be better. (One 780 Ti costs about as much as dual 770s). I think for now, if you can get a second cheap, a second 760 would be your better option, and then next gen maybe get a much better video card for cheaper. Maybe a leftover 780 Ti or something, even. From what I've been reading the 800 series may not even be that huge a step up, because of it being the first gen of a new manufacturing process, but I can't say for certain as I don't know a whole lot about these kind of things, all I can offer is my real-world experience with the 770.

I definitely wouldn't go by one guy's account on youtube. He definitely could have had other things going on with the PC (I would like to check out that video though). Look at the comments under the video. People are all saying they are getting the same framerates with a single 760 card or saying something is wrong with his SLI setup.

Look at the average fps on the review sites. Two 760s is the way to go. After you get another 760, sell both of them when the 900 series is released and get a 970/980 (or whatever they call them after the next gen). Going from a 760 to a 770 just doesn't make a lot of sense when you can simply add another 760 and get a serious performance boost (near 90%+ with some titles as opposed to a 20-25% increase with a single 770). A 770 is not bad by any means, but in your situation, I'd definitely pick up another 760 if your motherboard supports it and you have the budget for it.

The 780 Ti is still significantly better (and costs much less) than the Titan for gaming purposes and the Titan really isn't all that great for gaming when you consider its price, so I'm not sure why you're hung up on the Titan for this comparison. The Titan isn't really designed for gaming, as much as it is other video intensive applications (like things that use up a lot more VRAM than most games will). Also, we've already been over this and you already said by "outperforming" you meant price, so I'm not sure why you're bringing up benchmarks, but in regards to a 780 Ti it's not physically possible in any situation ever, for a 760, even in dual SLI, to outperform a 780 Ti (and a 760 in Triple SLI performs worse than dual, so don't even bother with that). There's not a real benchmark anywhere that shows a 760 in SLI outperforming a 780 Ti.

Also, this isn't just about framerates. What I'm saying about the 770 is it took two 760s to even be capable of running Battlefield 4 on Ultra. A single 770 runs BF4 on Ultra straight out of the box, at better framerates than the dual 760 set up in that video. His frame rates were no doubt a bit lower than normal because of the fact that he was running some recording software, but honestly not that much (Shadowplay is pretty lightweight on your system). But yes, I think dual 760s would at least perform as well as a single 770, maybe even outperform it by a bit, they may even come close to a single 780, but they won't outperform a 780, and definitely not a 780 Ti, etc. It's just not physically possible. Let's do the math:

Single 760 has 1,152 CUDA cores, 2GB GDDR5 @ 6,008 MHz on a 256 bit interface, SLI makes 2,304 CUDA cores, same memory specs (memory doesn't stack in SLI)
Single 770 has 1,536 CUDA cores, 2GB GDDR5 @ 7,010 MHz on 256-bit
Single 780 has 2,304 CUDA cores, equal to two 760s, but has 3 GB GDDR5 @ 6,008 MHz on 348-bit interface
Single Titan has 2,688 CUDA cores, 6GB GDDR5 @ 6,000 MHz on 384-bit
Single 780 Ti has 2,880 CUDA cores, 3GB GDDR5 @ 7,000 MHz on 384-bit

So, spec wise, you can see that dual 760s has as many CUDA cores as one 780, but it has less VRAM, on a smaller interface so it just won't perform memory operations at the same speed. However, even though the CUDA cores are the same, cards in SLI don't both perform at 100%. They perform more closely to 80% per card (and at Triple SLI it might be like 60% per card), this is why an equivalent single card is always the better option. So if you take those 2,304 CUDA cores and shave off 20%, it comes out to 1,834 effective cores. Obviously this math isn't an exact science as there's a whole bunch of different variables, but you get the point.

In any case, my point is yes, in your situation for the time being, you're better of going dual 760s instead of spending more money and being stuck with a leftover 760 you can't use, and getting a better video card later. All I'm saying is, don't set your expectations too high as to what 760s in SLI can do, because if you're expecting the performance of a single Titan or 780 Ti or even a 780, you'll likely end up being disappointed.

They're getting better FPS at lower settings with a single 760. It's not his SLI set up, it's that he's capable of running higher graphics now, at a playable FPS. However, I agree with your point about not worth the money to splurge for another higher-end GPU right now, especially since OP probably can't return the original 760 at this point, so it would've been a wasted $230+.

Personally, I think it's best to get the 760. You already have one, and it will give you performance similar to a 780, but you'll be spending a lot less.

BF4 at Ultra is such a beautiful game. Hope you love it. But yeah, Partpicker is a wonderful website, they have a version of the website for most regions so you can find what parts cost at different retailers anywhere you are and in most currencies.

Pcpartpicker is incredible for not only finding the cheapest prices and sorting everything, but also finding prices in different countries. Here in the US we have Newegg, and that's basically the one place I buy components, so I have no idea where to start when suggesting something to somebody in the UK.