display port link failure?

just bought a dp cable of ebay as my dvi wasnt long enough. and i keep getting a link failure message. and when i come out of a game the resolution is changing to 800x640 or something (normal res 2560x1440)

google search indicates something to do with one of the pins. should i return this cable? if so what do i need to get?

the cable is male to male 2m v1.2

Definitely sounds like the cable is bad, especially if it was a generic eBay special...

turned out it was amd External Events Utility. disabled it and working fine