SDRAM Page Closing Policy

Common Options : One Bank, All Banks

Quick Review

This BIOS feature is similar to SDRAM Precharge Control.

This BIOS feature determines if the chipset should try to leave the pages open (by closing just one open page) or try to keep them closed (by closing all open pages) whenever there is a page miss.

The One Bank setting forces the memory controller to close only one page whenever a page miss occurs. This allows the other open pages to be accessed at the cost of only one clock cycle.

However, when a page miss occurs, there is a chance that subsequent data requests will result in page misses as well. In long memory reads that cannot be satisfied by any of the open pages, this may cause up to four full latency reads to occur.

The All Banks setting, on the other hand, forces the memory controller to send an All Banks Precharge Command to the SDRAM interface whenever there is a page miss. This causes all the open pages to close (precharge). Therefore, subsequent reads only need to activate the necessary memory bank. This is useful in cases where subsequent data requests will also result in page misses.

As you can see, both settings have their advantages and disadvantages. But you should see better performance with the One Bank setting as the open pages allow very fast accesses. The All Banks setting, however, has the advantage of keeping the memory contents refreshed more often. This improves data integrity although it is only useful if you have chosen a SDRAM refresh interval that is longer than the standard 64 msec.

Therefore, it is recommended that you select the One Bank setting for better memory performance. The All Banks setting can improve data integrity but if you are keeping the SDRAM refresh interval within specification, then it is of little use.

Support Tech ARP!

If you like our work, you can help support out work by visiting our sponsors, participate in the Tech ARP Forums, or even donate to our fund. Any help you can render is greatly appreciated!