GTX 680 SLI Questions

[Danny942]

Hey guys! So due to some unexpected circumstances Newegg has given me $300 worth of store credit and I have some questions for you all. My current setup is as follows:
I7 3770 stock
Corsair 750w power supply
Asus P8Z77lk motherboard
Gtx 680 2gb
8gb ram
I'm thinking about using that money to go SLI with my 680. Before I do that though I have a few concerns.
1. My motherboard can support SLI, but has one PCI 3.0 slot and one PCI 2.0 slot. This won't interfere with anything right or cause driver complications?
2. Since my card is a bit older I can only find refurbished 680s on newegg. The one that is available is a PNY while mine is an Asus. This won't cause any problems right?
3. How complex is the transition from a one card setup to SLI? Concerning drivers and bios.
4. Is a 750w power supply adequate?
5. How much of a performance increase can I expect to see? I'm looking to run skyrim with various enbs and graphical mods as well as AAA titles like GTA V (when it finally gets here) at max settings.
6. Is this a wise investment? Would I be better off just saving more money and getting a 980 or something?
Thank you guys!

 

[pauls3743]

I'll answer as best as I can.

1. PCIe 2.0 is more than fine. What will matter more is whether the slot will be x8 or x4, if it's going to be x4 then I'd look at another solution. The manual will tell you what speed the 2nd slot will run at.
2. As long as they're both the same model i.e. both GTX 680s it will work. What will happen is that the card with the higher spec card will run at the speeds and capacities of the lesser card. There used to be a time when you had to use identical cards for SLi, thankfully NVidia worked that out but it didn't extend to other models of cards.
3. After installing the card I would recommend re-installing the graphics drivers, you also need to enter the NVidia control panel and enable SLi. The bios needs nothing.
4. If it's a good quality supply then yes. If you overclock I'd recommend getting a bigger supply.
5. This will vary greatly from game to game. Some games will almost double their frame rate, others may not even benefit as they don't support SLi, there are the odd game or two which will actually run worse if SLi is enabled. You will notice microstutter and some of it will be quite bad. I don't know what improvements you will get on Skyrim or the unrealised GTA V.
6. Personally, I don't think it is a wise investment. I always advocate a single powerful card over a pair of less powerful cards simply because when you come up against a game which doesn't support dual cards you don't take a performance hit. As a parting thought I'd looking at a GTX 970.

 

[Danny942]

Hey, thanks so much for the detailed response! How often will I experience micro stutter in my games? So do you think I will see better performance by purchasing a 970 or 980? I know it will probably be more consistent haha.