doing sli with 2 graphics cards different brands

[EEG SEXTANT]

alright so i have a gtx 770 gigabyte x3 4gb, would it be possible to sli that with any other gtx 770 4gb?
my motherboard supports it

 

[bignastyid]

Yes.

 

[EEG SEXTANT]

Yes.

would there be any downside?

 

[bignastyid]

Nope