ASUS EAH4870 Dark Knight 1Gb graphic issues

[Edenkai]

ok my husband and i recently got new pc parts. My husband got all new parts except for the video card. So he built his pc and put my old video card in since i got a new video card. ASUS EAH4870 DK/HTDI/1GD5 Radeon HD 4870 Dark Knight 1GB 256-bit GDDR5 PCI Express 2.0 x16 HDCP now when i had this in my computer it ran games just fine (except planetside 2). Now that its in my husbands system its having issues playing Blacklight retribution. it keeps telling him that the video card does not meet the min requirements. It says the video card is 256 megs when its a 1g card. But he can play Maxpayne 3 just fine on max settings. he has windows 8, Processor Intel(R) Core(TM) i5-3570 CPU @ 3.40GHz, and Memory (RAM) 8.00 GB. Any suggestions?

 

[Edenkai]

ok update, I think the onboard video card is the issue. But im not sure where in BIOS to disable it. my husband has a ASRock B75M-GL Micro ATX Intel mother board if that helps.