If they are small and square, I believe they are BGA.
The should have some writing on them, either Samsung or Infineon. And at the end of the long string of numbers/letters should be either 3, 3.3 or 2.8 (representing the speed rating of RAM).
3ns is rated up to 333MHz (666)
3.3ns is rated up to 300MHz (600)
2.8 is rated up to ~360MHz (~720)
I got some Infineon 3ns 🙁 Runs at 330MHz (660), not all that great.