Crossfire on PCI-Express 16x & 4x

[Cristian Dobre]

Hi ,
I have Gigabyte GA-970A-UD3P - it has 1 port pci x16 and one 4x
Video card Asus R9 270 can conect to pci-express 3.0.
I want to do crossfire. The performance will drop more than 15% ?. Is enough that 4x ?
or i need to buy a MB with 2 PCI 2.0 x16 ? ( 2x PCI 3.0 x16 is too expensive )

 

[prit87]

Corssfiring with 4x pcie slot is a waste you should not put any gpu lower than 8x pcie