Methods and devices for refreshing a dynamic memory device, (e.g., DRAM) to eliminate unnecessary page refresh operations. A value in a lookup table for the page may indicate whether valid data including all zeros is present in the page. When the page includes valid data of all zeros, the lookup table value may be set so that refresh, memory read, write and clear accesses of the page may be inhibited and a valid value may be returned. A second lookup table may contain a second value indicating whether a page has been accessed by a page read or write during the page refresh interval. A page refresh, by issuing an ACT−PRE command pair, and a page address may be performed according to the page refresh interval when the second value indicates that page access has not occurred.