18.1. Installing Processors

ProLiant servers ship from the factory with one or more processors installed. You can replace one processor with another or you can add additional processors.

Before installing a processor, you should be aware of these precautions:

• Processor socket 1 must be populated with a processor at all times. The system fails to boot if the socket is not populated.

• You should not mix processors of different types or speeds.

• You must correctly align the processor pins to seat the processor into the socket.

To install a processor, follow these steps:

1. Power down the server and remove the access panel.

2. Align the notched corner of the processor with the notched corner of the socket.

3. Insert the processor and close the locking lever on the processor socket.

4. Remove the plastic cover on a new, unused heat sink to expose the thermal interface material.

Warning

Always use a new heat sink with thermal interface material when replacing processors. Failure to use new components may result in damage to the processor.

5. Install the heat sink.

6. Carefully install the heat sink retaining clip and close the locking lever on the heat sink retaining clip.

7. Install a power-processing module (PPM) in the corresponding slot, if the slot is empty.

Warning

PPM slots must be populated when processors are installed. If PPM slots are not populated, the system does not boot.

8. Replace the access panel.

If installing an additional processor module, you also must install an additional voltage-regulator module (VRM). Processor modules acquired from HP will include the additional VRM.

To install a PPM or a VRM in a ProLiant server, refer to the Maintenance and Service Guide for that server.

You can access technical documentation and service advisories for ProLiant servers from the HP Reference Library site at http://h71025.www7.hp.com/support/home/selectproduct.asp?destination=reflib.

18.1.1 Mixing Processors

The desire for investment protection and a growing need to scale processing power make the ability to mix processors in dual-processor and multiprocessor systems a significant customer benefit.

To ensure full protection and support under manufacturer warranties, always configure processors according to manufacturer guidelines. In addition, you must reconcile the guidelines of the processor manufacturer, the server manufacturer, and the operating system vendor.

! Important

Four-way platforms, starting with the Intel Xeon processors, no longer support processor mixing.

18.1.1.1 PROCESSOR STEPPINGS

Processor steppings are versions of the same processor model with slight variation, usually to improve performance or manufacturing yield. Each stepping requires changes to the system ROM.

Each Intel processor stepping has a microcode patch for inclusion in the system ROM. The microcode patches are stored in a table within the system ROM. HP and other server vendors must continually add newly released Intel patches to keep their ROMs current.

If a processor is installed in a ProLiant server that does not contain the correct microcode in the current system ROM, the ROM generates the following error message to prevent the user from operating the processor with the wrong microcode:

 UNSUPPORTED PROCESSOR DETECTED. SYSTEM HALTED. 

Example

If a customer has a four-way ProLiant server containing two processors and decides to upgrade by adding two more processors, the new processors could be of a different stepping. To ensure that the system ROM contains the latest microcodes, you must flash the ROM on that server using an updated System ROMPaq before installing the new processors.

Tip

After a processor has been installed, stepping identification can be problematic because a heat sink typically covers the top of the processor chip. Utilities provided with operating systems might help. You also can use the Survey Utility to view the steppings of installed processors.

18.1.1.2 INTEL SUPPORT FOR PROCESSOR MIXING

Based on the information available on the Intel Web site at the time of this writing, Intel supports mixed steppings of processors only under these conditions:

• All processors in a system must have identical family and model numbers as indicated by the CPU ID instruction.

• All processors in a system must operate at the same frequency that is, at the highest frequency rating commonly supported by all the processors.

• All processors in a system must have the same cache size.

• The processor with the lowest feature set must be the bootstrap processor.

18.1.1.3 OPERATING SYSTEM SUPPORT FOR PROCESSOR MIXING

Like Intel, operating system vendors support the mixing of processors only if all processors in a system

• Have identical family and model numbers.

• Operate at the same frequency.

• Have the same cache size.

The processor with the lowest feature set must be the bootstrap processor. The most common operating systems typically do not inhibit the operation of servers containing multiple processors with different steppings.

Note

Processor steppings were introduced in Chapter 2. Refer to that chapter for a discussion of industry processor stepping guidelines.

18.1.1.4 HP SUPPORT FOR PROCESSOR MIXING

HP supports the mixing of processors in ProLiant servers under the following conditions:

• All processors in the server must be of the same processor family and model. For example, Intel Pentium II Xeon processors cannot be mixed with Pentium III Xeon processors.

• The 500/550MHz Pentium III Xeon processors cannot be mixed with 700MHz or higher-frequency Pentium III Xeon processors.

• The core frequency for the 900MHz Pentium III Xeon processors must be locked. The 900MHz Pentium III processors cannot be mixed with any other Pentium III Xeon processors.

• The core frequency of each processor in the server must be set to the frequency of the slowest processor. Switches on the system board (or the ROM) can be used to reset the frequency of Pentium Xeon processors. However, Pentium III and Pentium II processors are locked to the frequency ratio at which Intel intends them to run. HP does not support mixing Pentium II or Pentium III processors with different frequencies.

• No processor core should be set to a frequency higher than the processor is rated for.

• When using Pentium II Xeon or Pentium III Xeon processors with different cache sizes, the processors must be installed in pairs with the same cache size: the first pair in Slot 1 and Slot 2; the second pair in Slot 3 and Slot 4; the third pair in Slot 5 and Slot 6; and the fourth pair in Slot 7 and Slot 8.

• The processor with the lowest stepping must be installed as the bootstrap processor.

! Important

Four-way Gallatin-based ProLiant server platforms, starting with the Intel Xeon processors, no longer support processor mixing.

To ensure that a ProLiant server containing mixed processors operates correctly, flash the system ROM before installing the processors.

To obtain the latest HP ROM available on the HP Web site, visit http://h18007.www1.hp.com/support/files/server/us/index.html.

You can find more information about processor mixing at http://h18000.www1.hp.com/products/servers/processor-mixing/.