NVIDIA SLI questions

So, like the title suggests... I’m currently running an EVGA GeForce GTX 780 Ti, and my long-term plan is to pick up a second one to set up an SLI configuration. Since it looks like these cards are becoming a bit of a unicorn on the market, I wanted to ask what actually matters when choosing a card for SLI. Aside from needing two available PCIe slots, do things like clock speeds or specific models really make a difference?

By the way, I'm using a Corsair RM550x right now—do you think that power supply can handle two EVGA GeForce GTX 780 Tis?

An EVGA GeForce GTX 780 Ti can run in SLI with an NVIDIA GTX 750 Ti since they are essentially just rebranded or overclocked versions of the same architecture. Similarly, you could pair a 280x with a 7970 in SLI. Personally, though, I wouldn't bother with SLI. You’d also definitely need a beefier power supply.

EDIT

Here's a test for you: http://www.legitreviews.com/amd-rade...testing_126124

With those cards pulling 2x150W plus an overclock, and the CPU sitting near 200W... I guess it would be a struggle to keep things stable.

NVIDIA GTX 750 Ti + 130W CPU + overclocking (it’s basically the same draw) — that puts us at 508W click

that Seasonic unit provides 40A on the 12V rail (480W)

That CPU is pushed pretty hard... I saw a review where it was pulling 260W at 1.4V and 4.65GHz.

Give me a break... it’s freezing outside and you've got the case sitting open on the balcony... just kidding 😬