@SarahGen-- My dad has been drinking ginkgo tea daily for several months now. He still can't remember where he put the house keys but his concentration has improved.
He used to have very poor concentration and would jump from thought to thought during conversations. He is definitely better at following a conversation now. He says he is working better at the office too.
So I'm not sure if ginkgo has benefits for memory, but it seems to help with concentration.