AMD is colloquially referred to as "Team Red" in computer hardware circles. Intel is "Team Blue" and Nvidia is "Team Green."

The phrase "seeing red" is a fairly common idiom in my experience in American English. This refers to the matador's traditionally red sash used in bull fighting. Red is believed to draw inordinate amounts of bull attention and make them angry.

The use of "seeing red" is a bit strange, as the idiom is typically associated with anger and a pending bull charge, potentially metaphorical.

Thus, AMD -> Team Red -> seeing red -> bulls.