Dell Precision 490 User Manual
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Memory
Dell Precision™ Workstation 490 User's Guide
Fully Buffered DIMM (FBD) Memory Overview
Addressing Memory With 4-GB or Greater Configurations (32-bit Operating Systems Only)
Your computer supports fully-buffered ECC DDR2 memory only. For more information on the type of memory supported by your computer, see
Specifications
.
Fully Buffered DIMM (FBD) Memory Overview
For optimal performance, fully buffered DIMMs (FBDs) should be installed in matched sets of four. This enables quad-channel operation and provides the
highest memory bandwidth. The sets of four must be matched in size, rank, and organization. This information can normally be found on the FBD label. For
example, the label of each FBD in a set of four might read: 1G 2R x8, in which 1G represents the size of the memory module, 2R represents the number of
ranks, and x8 represents the organization.
Memory Installation
Fully buffered DDR2 memory modules can also be installed in pairs of two; in this case, the computer will continue to operate, but with a slight reduction in
performance. The pairs must be matched in size, rank, and organization.
Install memory modules in order of their labels on the system board; matched sets of four should be installed first into DIMM slots 1-4 and then into DIMM slots
5-8 on the system board. Pairs of memory should be first installed into slots DIMM_1, and DIMM_2, then DIMM_3 and DIMM_4, and so on.
Addressing Memory With 4-GB or Greater Configurations (32-bit Operating Systems
Only)
This computer supports a maximum of 32 GB of memory when eight 4-GB DIMMs are installed. Current 32-bit operating systems, such as Microsoft®
Windows® XP, can use a maximum of 4 GB of address space; however, the amount of memory available to the operating system is less than that installed.
Certain components within the computer require address space in the 4-GB range. Any address space reserved for these components cannot be used by
computer memory.
The following components require memory address space:
l
System ROM
l
APIC(s)
l
Integrated PCI devices, such as network connectors and SCSI controllers
NOTICE:
Before you install new memory modules, download the most recent BIOS for your computer from the Dell Support website at
support.dell.com.
NOTE:
Memory purchased from Dell is covered under your computer warranty.
NOTICE:
Full-length heat spreaders (FLHS) are required for any memory in a memory riser and for 667 MHz DIMMs.
1 fully buffered DIMM
2 fully buffered DIMM with full-length heat spreaders
3 information label
NOTICE:
Do not install non-ECC or unbuffered memory modules. Doing so may cause the computer not to boot.