!!!HELP:memory on de2 board

hello. i cannot find a compatible SRAM in SOPC for my de2 board. on my de2 board, it uses SRAM IS61LV25616AL 512kb. however, in sopc, it has IDT71V416 and cypress only. i tried to use IDT71V416 but the number of bit generated is more than the one on board can support. pls assist. i choose IDT71V416 and set the memory to 512kb.