Difference Between 1 Graphics Card or 2 Graphics Cards?

[peenter]

I am building a new PC, have been needing an upgrade for a while.
This is what I have so far: http://pcpartpicker.com/p/hbPGBm
I wanted to know if I added an extra gtx 960 if the performance would be big difference.
Also I wanted to know if I should get the intel i7 6700k instead of the i5. Feedback is appreciated!

 

[greens]

you're waaaaay better off with one good GPU than two low end GPUs.

Get a GTX 970 instead of two 960s

 

[VincentP]

To use two video cards in a game, you need to run them in SLI.
The performance is about 50% faster than a single card, but there can be a lot of problems with drivers, game support and stuttering.
Generally, it's much better to get a single faster card rather than two slow ones.

You also need motherboard support for SLI, and the board you have chosen does not support SLI. This is mostly because the board has one PCI-E x16 slot that can operate at ful speed and any other can only operate at X4 speed using the motherboard chipset lanes rather than the CPU lanes.

Right now, the right choice would be a GTX 970. Performance and cost would be similar to two GTX 960 cards, but performance would be a lot more reliable, power usage would be less and you wouldn't need a more expensive motherboard.
Nvidia is releasing the GTX 1070 next month to replace this card, with much better performance at a similar price. If you can wait until July you should be able to pick up your choice of GTX 1070 cards.

Power supply you have chosen is fine, but you can pick a lower wattage model if not using SLI. All you really need is a good quality 500W supply, but anything up to 650W would be sensible enough with plenty of headroom for expansion.

The Core i7 would offer very little performance gain in games compared to the i5. You also couldn't overclock using this motherboard, and this is what the K models are for. I would just stick with the Core i5.

 

[why_wolf]

agree with the single superior GPU over trying to SLI two lower tier cards. Using two cards in SLI does not give you double the power.

What are you using this computer for? If it's just games you'll be perfectly fine with an i5. i7s extra hyper threading goes essentially unused by games.

 

[InvalidError]

Single faster GPU = predictable performance in all games.

Two slower GPUs = requires game-specific driver optimizations to work well, some games have performance issues with SLI/CF and many simply will not use more than one GPU.