What You Need For An SLI Build
In order to build a SLI-capable system, you need the following:
- A motherboard with at least two free PCIe x16 slots, operating in at least in x8 mode (Nvidia does not support SLI on x4 links). Pretty much all LGA 2011, LGA 2011-v3 and LGA 1150 motherboards satisfy this requirement.
- Two (or more) identical Nvidia-based cards that support SLI, or a dual-GPU card like the GeForce GTX 690 or Titan Z. Generally, different cards won't do the trick.
- A suitable power supply. Increasing the number of GPUs in a system rapidly increases its power requirements. Take that into account when you choose your PSU.
- An SLI bridge. This is generally provided by your motherboard's manufacturer as a bundled accessory.
- The latest Nvidia drivers. If you're reading this article, we're pretty sure that you know that you can grab these from Nvidia's website.
In addition, you'll want a relatively enthusiast-oriented CPU, especially if you're shooting for high frame rates (such as to power 120+ Hz displays) more than better eye candy. For reference, the Core i7-4770K overclocked to 4.4 GHz that we used in these tests appeared to cap out at roughly 150 FPS at 1440p in most applications.
Once all of this is sorted out, you can go ahead and enable SLI in the Nvidia Control Panel.