I have a friend who has the 7900x and loves it but I'm waiting for the 1950x to come out. I game on my system but render videos also so threadripper might be a better system for myself. I would recommend waiting to see how it preforms in real world tests rather than synthetic benchmarks
The i7 has hyper threading which will make it better for cpu heavy tasks such as video editing and streaming. If you are only gaming the i5 will be fine but the i7 has the 4 logical cores and will bet better for longevity, imho.
Just double check to make sure sli is enabled because whenever there is a new driver it automatically disables sli and a new driver came out the other day