Fully populated memory on X7DWA-N with Samsung 8GB M395T1K66AZ4-CE66. But it only shows 48GB memory. The BIOS version on the motherboard is 1.0b (12/21/07). It there any setting needed change in BIOS in order for total of 64GB memory is detected.
Please update the BIOS to 1.2c (11/19/10) which contains more latest release microcode code release by Intel which will solve the issue.