SLI x2; x3 and x4

Hi Folks,
I was wondering if the illuminati of this board can enlighten me.  Everything I've been reading is that x2 SLI is really the sweet spot.  Anything beyond that has rapidly diminishing returns to the point where x4 basically contributes next to nothing.  Would it be wiser to do something as x2 and then use one of the cards as a PhysX card?  I'm curious as to what people think about this and really what they'd feel is a wise investment.  Sorry for the dumb question.  Thanks!!

PS:  Bprat, I'm sure you'll show up in this thread - congrats on 10K posts!!

Thanks for the link.  I was asking if it was x2+PhysX vs. x3 SLI was a better set up. So x3 sounds like the way to go then.  There's minimal gain with x4 considering the cost.  I wonder how the 980s scale - I would think probably in a similar manner.  Would the x99 platform make a difference due to the better bandwidth on the higher end MBs?

From what I've read, I agree with you.  The x16 doesn't seem to provide gains which is odd.  Would that be a hardware thing or a driver thing?

Keep in mind that newer cards offer better scaling when it comes to sli. I'm assuming we're only talking about nvidia here. AMD actually has offered much better scaling in terms of multi gpu set ups for a good while now.

In my opinion, the 3 gpu set up is the sweet spot for max performance vs price ratio (when we're talking about 1,2,3 & 4 card set ups.

But the new GTX 980 actually overs some great scaling all the way up to 4 cards. But, as per my previous statement, the 3 card GPU is really the sweet spot. It's the last spot you see some good jumps.

Now Bprat is right. You're going to be getting like 80% with a second card and about 50% with a third. I say third is the sweet spot because 50% is a big jump compared to say 10-20% for a 3rd to 4th.

As far as PCI lanes go. We don't have any cards in todays consumer marker that use up 40 lanes. Hell, the difference between a x16 and x8 is like 1-2 fps usually.

Basically it depends on the card on how many you'll want. a GTX 760 is a great card and two of them are amazing. But I wouldn't buy three. While a GTX 780 is an amazing card all the way up to three, but I wouldn't buy a 4th. A GTX 980... I'd buy at very least 3... and come better drivers possibly a 4th just because scaling is getting so good finally.

*This is under the assumption that the game profiles nicely with sli set ups*

It didn't at first. At the very start of the GTX 980 release, it was just barely beating the GTX 780, with the GTX Titan Black and GTX 780 Ti out performing it. Now, in a single card set up, the GTX 980 wins at 1080p, 1440p, and just barely at 4k over all the cards.

And drivers are just starting to mature, so it's definitely getting better and better with scaling. Keep that in mind. Performance continue to only get better. Especially with DSR support, which I personally have tested, and it works amazingly.

Oh yea. 3 is the cap right now in terms of sweet spot. Now in just general terms of performance jumps, yes two in sli wins. But in terms of getting noticeable performance jumps... 3 is where it really stops. Three is, in my opinion, the current sweet spot for performance gains.

I disagree completely.

Firstly, I posted a review of PCI lanes to show the difference between 8x and 16x. It's not even up for debate on if it's worth consideration or not. It's not.

As for multi-gpu setup's. While AMD HAD been known to scale better than Nvidia. Nvidia is changing that with their scaling of the GTX 900-series.

Also in almost all cases there is major benefits at 1440p to have a dual card set up over a single card. 1440p games at ultra settings can still be taxing. While they may not eat up all of your 3GB of vram on your GTX 700-series cards, they will still eat up everything else. You'll notice a nice difference in ultra settings in some games with a single card vs a sli set up. We're talking about 40fps vs 70fps. In some games, that's a big noticeable difference, especially if you're into shooters like CoD, BF, etc...

Nvidia drivers are just too good right now to not consider nvidia over AMD. AMD needs to do something big to even get back in the game. Outside of picking up a R9 295X2 card, there's not a single AMD card that would grab my attention. I'd rather pick up a GTX 970 over an R9 290X.

Hell you can get a GTX 780 Ti Classified from EVGA for under $400 brand new, but regardless. You made two points. AMD > Nvidia for multi-card configs and Single card for 1440p gaming.

I disagree on both fronts. But, thankfully we are allowed to have our opinions on this and go with the builds we want.

Shadow play, power consumption, etc... Too much good to even make me blink an eye at amd at the moment. DSR alone is freaking amazing. If only amd could offer either better performance, less power, less heat, less noise, or better features. Nvidia is just killing it. :/

No clue but Nadia is also releasing 8gb 970s and 980 in November or December... AMD is a lost cause until we see the 20nm 300 series