The memory explicitly offered as nvidia compatible. You do not do it in the Dell Optiplex 740. It is no sticker on the memories. Unfortunately I have no other PC where you could test them to see what I got here. In my Recherschen I found the vote neither phone number nor address. On the side of CM3 there is no Contact Notes. Mir the only option on Amazon to contact and ultimately zurückzuschiken these things.