help me to choose
Sapphire AMD/ATI VAPOR-X HD 7950 OC with Boost 3 GB GDDR5
ZOTAC NVIDIA GTX660 Ti 2GB AMP! Edition ( ZT-60804-10P) 2 GB DDR5
Sapphire AMD/ATI HD 7870 2GB GDDR5 Flex Edition 2 GB GDDR5 Graphics Card
Sapphire AMD/ATI VAPOR-X HD 7950 OC with Boost 3 GB GDDR5
ZOTAC NVIDIA GTX660 Ti 2GB AMP! Edition ( ZT-60804-10P) 2 GB DDR5
Sapphire AMD/ATI HD 7870 2GB GDDR5 Flex Edition 2 GB GDDR5 Graphics Card