“Real Housewives of Atlanta” star Porsha Williams has a new girlfriend … and Porsha was swaggin’ and surfin’ and breakin’ it down low for Patrice “Sway” McKinney‘s birthday this weekend!

Porsha and her new love Patrice were seriously boo’d up at the event … with some footage that might not pass the censors for the show!

Porsha and McKinney — not to be mistaken for Porsha’s ex, Dennis McKinley, with whom she shares a daughter — just hard-launched last week with a couple’s pic in front of a Christmas tree.

This comes fresh off the heels of her alimony win against ex-hubby Simon Guobadia. The victory came over the summer when a judge reportedly awarded Simon to pay $40,000 per month for 15 months. Porsha also just left behind some air-travel drama, cleared after getting into a dispute with a passenger on a recent Delta Airlines flight.