arestavo
Hopefully this FAQ will set you in the right direction:

No, you can't just SLI any EVGA 970 with another, or from a different manufacturer unfortunately. It's the only model with this severe limitation AFAIK.

Thanks a ton for the info. Now, if I could only get E-Bay sellers to properly list and describe their cards, I might be able to upgrade my system.

Cool GTX
 
 
Ask for the serial number
 
Go here:
 
This tool tells you the number of days of warranty left on the EVGA product
 
Understand the
 
Such as extended warranty is Not transferable
 
Good hunting
 
Cost aside, One GTX 1080 (maybe even 1070) will have more Graphics Power and use less energy than two 970
 
What resolution is your monitor, what are you going to do with your system ?

My GPU-heavy computing involves mostly creating animations with Blender, and occasionally playing Cities: Skylines (a serious resource hog). I'm running two 2560x1440 monitors on an i7-7700K, 32GB RAM system. PassMark says that the 970 scores 8560 on their benchmark test and the 1080 scores 11,993. The Blender people say that adding a second 970 should up my render speed by about 70%, which equates to a score of 14,552 (8560*1.7), which is 21% faster than the 1080. Am I missing something? The thought of using less power is attractive... the one 970 I have has already turned my PC into a space heater... two could be unbearable. The increased memory of the 1080 is also a plus. The decision to go with a second 970 is based mostly on cost... the Titan XP scores 13,959, still below the (presumed) dual 970 score, and is way more than I want to spend on what is basically a time-wasting hobby. I really appreciate your response.

PS. I just found blenchmark.com, a site that has a Blender benchmark blender file. A single 970 scores 83 seconds, dual 970s score 39-44 seconds, and a single 1080ti scores 54-57 seconds.

Cool GTX
Wow, surprised by that
 
The math does not add up that two 970 are faster than a single 1080Ti ..... obviously not a Cuda core or memory intensive app --> like Folding is
 
I do not use blender
 

 
 
and that Folks is why You should do your homework...... I stand corrected
 
 
 
 
     Wonder if there is a free "trial version" of Blender --> so you could bench some of your Rigs ? 
 
 
     
 

Blender is Open Source, always free. It's a lot of fun, but be advised that the user interface is a wreck (very steep learning curve)... and they've long since passed the point where it's feasible to re-write it from the ground up to make it more user-friendly.
 
Again, much obliged for your answers.

The 970 SLI compatibility problems with so many other 970s is a major ball ache...  I want to SLi mine but can never get hold of a 970 FTW at a good price, it's all + versions or other cards at good prices... I wonder why the 970 is such a pain in the ass for this?