Any benefit of SLI'ing 2 different brands of the same GPU? Or performance loss?

[ahualoa]

Are there any performance benefits of running 2 different manufacturers of the same card? Let's just say for example a EVGA hybrid 980 ti with a Gigabyte G1 980 ti. Would this have a performance benefit over 2 of either card? Or would it just operate at the rate of the slower card?

 

[Gam3r01]

Both would operate at the speed of the slowest card.