PowerEdge 6650 Memory Questions


1.       What type and size memory can I install in my system?

2.       What memory features does the PowerEdge 6650 support?

3.       Memory Module Installation Guidelines

4.       Why Does my operating system only see 256MB available memory?

5.       Why Does my operating system report less than the 4Gb (or more) that is installed?

6.       Spare Parts and Upgrades


1.       What type and size memory can I install in my system?

The PowerEdge 6650 supports up to 16 PC1600 (DDR200) or PC2100 (DDR266), in 128MB, 256MB, 512MB, 1GB and 2GB DIMM sizes, for a total memory capacity of 32GB, if the latest System BIOS is installed.

Any time you update the System BIOS, it is advised to update the ESM Firmware.

This system was originally shipped with PC1600 (DDR200) but due to availability was soon changed to PC2100 (DDR266) compliant ECC-Registered DIMMs.

Do not mix PC1600 (DDR200) and PC2100 (DDR266) in the same system.

Note, the motherboard is only a 400MHz FSB, the PC2100 (DDR266) DIMMs will only run at the PC1600 (DDR200) speed.



2.       What memory features does the PowerEdge 6650 support?

The PowerEdge 6650 memory interface supports ECC, Memory Interleaving, Memory Mirror, Spare Bank Memory and Chipkill technologies.

The PowerEdge 6650 memory system resides on two separate memory riser cards, which are attached to the system board via a single 216-pin HDM+ type connector. The two memory cards together provide 288-bit wide memory support.

Note: Both memory cards with at least two DIMMs each need to be installed in the system to complete POST.

ECC
Error Checking and Correcting (ECC) support means that the system can detect and correct any single-bit memory errors that may occur without interruption of service.

Memory Interleaving
The PowerEdge 6650 supports 4-way interleaved memory configurations to reduce latency compared to non-interleaved implementations.

The DIMMs need to be inserted in sets of four (there are four banks, each consisting of four interleaved DIMMs). One bank consists of two DIMMs on each memory card. The banks must be populated in order so that if only one bank is present it must be Bank 1. To support memory interleaving the memory capacity must be identical within a given bank, however, the capacities for two separate banks can be different.

Spare Bank Memory
Your system features redundant memory, called which provides the system with a failover memory bank when an active memory bank has excessive single-bit errors. This failover occurs without the need to halt or restart the system. You can enable this feature in the System Setup program.

To enable the Redundant Memory option in the System Setup program, all memory slots in the system must be populated, and all memory modules must be of the same type and size. The redundant memory options vary according to the number of populated memory banks and whether identical memory modules are installed in each bank:

• Disabled — One or more banks are not populated, or not all memory modules are of the same type and size.
• Disabled and Spare Bank Enabled — All three memory banks are populated with memory modules of the same size and type.

Chipkill
The PowerEdge 6650 supports chipkill on only the 512MB, 1GB and 2GB DIMMs. Chipkill technology maintains system data integrity, even in the event of the failure of an entire DRAM chip within the memory array. Chipkill technology corrects more multiple single bit errors, that otherwise the ECC would have not be able to correct and would have caused a server shutdown.

For more information about the System Memory Features, see these documents:
Information Update
1-GB Memory Module Information
Information Update — 1-GB 512-Mb Memory Modules



3.       Memory Module Installation Guidelines

The 12 DIMM sockets are divided into three memory banks. install memory modules in matched sets of four, two in each memory riser card. Install a pair of memory modules in socket BANK1_A and BANK1_B before installing a second pair in sockets BANK2_A and BANK2_B.



4.       Why Does my operating system only see 256MB available memory?

A function called "OS Install Mode" is currently enabled in the system BIOS. This function limits the amount of system RAM available to the operating system to 256MB, and is necessary for installations of older operating systems to complete.

More information on this function and how to enable/disable OS Install Mode can be found HERE.



5.       Why Does my operating system report less than the 4Gb (or more) that is installed?

Systems that support hot-plug, hot-swap, and hot-add PCI capabilities, such as the PowerEdge 6650, with 4GB or more of physical memory installed may not report or have access to all physical memory. An indication of this is the operating system reporting less available memory than the amount of memory physically present in the system.

Hot-plug, hot-swap and hot-add PCI capabilities require that a certain amount of memory in the upper range of the 4GB address space be reserved. PCI devices installed in a system require all of their resources to be defined and mapped in the 32-bit address (4GB) space. The Flash Memory and APIC controllers are located at the top of memory at address 0xFEC00000 and above, other PCI devices are defined below this address range. Physical memory, which exists in this high address space, may be unusable by most operating systems.

Windows operating systems that support hot-plug, hot-swap, and hot-add PCI capabilities have this limitation by design, with the exception of Microsoft Windows 2000 and 2003 which uses a 36-bit address space that allows you to use the /PAE (physical address extension) switch in the boot.ini file to reclaim this memory.

In Windows 2000 and 2003, using the /PAE (physical address extension) switch in the boot.ini file will reclaim this memory because it uses a 36-bit address space.

This Microsoft Knowledge Base Article addresses this issue.



6.       Spare Parts and Upgrades

Below are Dell part numbers for various DIMMs we offer for the PowerEdge 6650. These modules were originally PC1600 (DDR200) but due to availability were soon changed to PC2100 (DDR266) compliant ECC-Registered DIMMs.

Note, the motherboard is only a 400MHz FSB, the PC2100 (DDR266) DIMMs will only run at the PC1600 (DDR200) speed.

Note Non-registered and Non-ECC DIMMs are NOT supported in the PowerEdge 6650.

PC1600 (DDR200)
These DIMMs are only available refurbished and should only be used in systems with existing PC1600 (DDR200) DIMMs installed.

0Y381       128MB,200M,16X72,4K,184,R
8T413       256MB,200M,32X72,4K,184,R
9T440       512MB,200M,64X72,8K,184,R

PC2100 (DDR266)

311-1959       1GB DDR,266MHZ,4X256 DIMMS
311-1961       2GB DDR,266MHZ,4X512 DIMMS
311-1962       4GB DDR,266MHZ,4X1GB DIMMS
311-2481       8GB DDR,266MHZ,4X2GB DIMMS (includes 2 memory risers)

Please note that the contents of the above part numbers are subject to change over time, as is availability of those parts.

We recommend contacting our Spare Parts department at 1-800-372-3355 for pricing, availability, and purchasing of all the above parts.


Message Edited by DELL-Mark A on 09-15-2004 07:40 AM