U will need about 650W BRANDED PSU, not generic crap.
Usually those psu comes with the 2-6 6 pin connect cause they need to support crossfire/sli
my psu ranking
Seasonic(extinct in ca)->Antec(made by seasonic huhuhu)->corsair(anything except cx series)->evga. The rest brands arent top psu tiers.
Generic psu are usually hit or miss. Most would do well at 40-50% of advertised load
So if you would test your luck, go get a two 4pin to 6 pin connector at your local store or ebay, they come at around 3$
Warning: I am not responsible if anything burn