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The Latitude™ D620 uses DDR2 memory. At 667 MHz, this memory offers a significant increase of memory performance over
the D610 platform. This system supports 533 MHz as well as 667 MHz modules, but Dell only offers 667 MHz modules at the
time of purchase. DDR2 memory is keyed differently from both SDRAM and DDR to prevent you from installing the wrong type of
memory into the system.
Memory Configuration
This system has two user-
accessible slots for installing memory. One is located on the bottom of the system (DIMM B), and the
other is located beneath the keyboard (DIMM A). Both are CRUs. Dell offers three different size memory modules that can be
used in these slots: 256 MB, 512 MB, and 1024 MB. These offerings allow memory configurations as follows:
*Indicates dual-channel interleaved (fastest) configuration
Troubleshooting
Memory errors on the system display the new ON-FLASH-FLASH or ON-FLASH-
ON failure code. If all memory fails, the LCD
does not turn on. Troubleshoot for possible memory failure by trying known good memory in the memory slots on the bottom of
the system as well as under the keyboard.
4 GB Memory Barrier
The Latitude D620 support a maximum of 4 GB of memory. Current operating systems such as Microsoft® Windows®
XP can
only use a maximum of 4 GB of address space. However, the amount of memory available to the operating system is less than 4
GB. Certain components within the computer require memory address space in the 4 GB range. Any memory address space
reserved for these components cannot be used by the operating system.
Memory
Slot A Slot B Total Memory
256 MB None 256 MB
512 MB None 512 MB
1024 MB None 1024 MB
2048 MB None 2048 MB
256 MB 256 MB 512 MB*
512 MB 256 MB 784 MB
1024 MB 256 MB 1280 MB
2048 MB 256 MB 2304 MB
512 MB 512 MB 1024 MB*
1024 MB 512 MB 1536 MB
2048 MB 512 MB 2560 MB
1024 MB 1024 MB 2048 MB*
2048 MB 1024 MB 3072 MB
2048 MB 2048 MB 4096 MB*
NOTE:
This is a limitation of a 32-bit architecture: the system can only address 4 GB of allocated memory. Allocated
memory is made up of physical RAM and any I/O space needed by devices. Normally this is not a problem, but
when a system has 4 GB of physical memory, the memory addresses needed to map RAM overlap the space
needed for the I/O devices. In this case, the need for I/O space takes precedence, and the amount of RAM visible to
the operating system is limited to 4 GB minus the I/O allocation.
Printed 2/22/2010 11:17:19 AM
Latitude™ D620
For Dell Employees Only
Expires 2/23/2010 11:17:19 AM
Memory
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