Is it possible to use DRAM with microcontroller AVR? Yes, it is possible. Jesperh has proved it. He hooked up a DRAM to a small processor (in this case an Microcontroller Atmel 8515), and handle the RAS/CAS sequencing and refresh in software.
The type of DRAM is Hitatchi M5M44800, a 512k*8 DRAM!. Bigger than the original memory of microcontroller AT90S8515 that is 512 byte RAM. The project use C to programm it. The chip required small power consumption, only takes about 2-3 mA when just refreshing and with a low access rate.
For more detail: Interfacing DRAM Memory using AVR microcontroller