second r9 290x not detecting

[semverhoef]

me and my brother always gamed togheter, now he bought a 1070, so i got his r9 290x gpu and wanted to crossfire, i put the second card in but only 1 cards shows my monitor and the other card does spin (the fan) but my pc doesnt show the second card.
both are in a pcie x16 slot, my specs are
8gb ddr3
sabertooth 990fx 2.0
2x r9 290x reference asus
amd 8350
1200 watt gold power evga power supply

please help

 

[sx57]

hello.maybe you need to install the driver for the second card.have you checked device manager to see if it is detected there ?

 

[semverhoef]

i used another power cable and it worked, stupid me