How safe are PCI-E Y Spliters on a GPU?

Eleutherios Psoras

Honorable
Jan 27, 2014
2
0
10,510
Long story short I am planning on buying a 780 Ti in the next few weeks or so but my current power supply does not have the connectors needed to power it (2x8 pins).
I considered buying a new PSU (Same wattage at 650w but with way more options and fully modular) until I came across this.
http://www.newegg.com/Product/Product.aspx?gclid=CMf4tfP4n7wCFRNp7AodC1YAOw&Item=N82E16812201038&nm_mc=KNC-GoogleAdwords&cm_mmc=KNC-GoogleAdwords-_-pla-_-Internal+Power+Cables-_-N82E16812201038&ef_id=UucmLwAAAeKAco5Y:20140128033823:s#top[1]
This can split the lone 6 pin PCI-e into 2x6 pin, 2x8 pin, or one of each whenever it's needed.
My question is how safe is it to have the power of 2x8 pins in my GPU all coming from a single 6 pin. Also will there be the chance that I may not get the same power that I would from a dedicated 2x8 pin from a newer PSU and the GPU will perform worse with less power? Thanks.