1 the computer must have at least one pair of dimms installed in the dimm connectors for each microprocessor installed.
2 the system board contains four dimm connectors for microprocessor 1. your computer comes with one pair of dimms installed in the dimm connectors on the system board.
3 if you install a second microprocessor, the board that comes with the microprocessor option (microprocessor board) contains four dimm connectors for microprocessor 2. you must install at least one pair of dimms in the dimm connectors on the microprocessor board.
4 you can add a second pair of dimms for either microprocessor at any time. it is not necessary to add a second pair of dimms for microprocessor 1 before adding a second pair of dimms for microprocessor 2.
5 the dimm options that are available for your computer are 512 mb, 1 gb, and 2 gb. your computer supports a minimum of 1 gb and a maximum of 16 gb of system memory.
exception: although your computer supports a maximum of 16 gb of system memory, the microsoft windows xp operating systems recognize and support a maximum of 4 gb of system memory.
6 your computer comes with two 512 mb or 1 gb memory dimms installed.
7 install only 2.5 v, 184-pin, double-data-rate (ddr), pc2700, registered, buffered synchronous dynamic random-access memory (sdram) with error correcting code (ecc) dimms. these dimms must be compatible with the latest pc2700 sdram buffered dimm specification. for a list of supported options for your computer, go to http://www.ibm.com/pc/; then, select your country and navigate to the list of options for your computer.
8 dimms must be installed in matched pairs. the dimms in each pair must be the same size, speed, type, and technology as each other but do not have to match other pairs. you can mix compatible dimms from various manufacturers.
9 the first pair of dimms on the system board are installed in dimm connectors 1 and 2. if you install a second pair of dimms for microprocessor 1, install the pair in dimm connectors 3 and 4. the following illustration shows the system board dimm installation sequence.
10 if you install a second microprocessor (microprocessor 2), install the first pair of dimms for the microprocessor in dimm connectors 5 and 6 on the microprocessor option board. if you install a second pair of dimms for the microprocessor, install the pair in dimm connectors 7 and 8 on the microprocessor board. see “installing a second microprocessor” on page 56 for more information about the microprocessor option. the following illustration shows the microprocessor board dimm installation sequence.
11 your computer supports two-way memory interleaving across the memory banks for each microprocessor.
12 the amount of usable memory will be reduced depending on the system configuration. a certain amount of memory must be reserved for system resources. the bios will display the total amount of installed memory and the amount of configured memory. to obtain a full 16 gb or more of usable memory, you must install a second microprocessor and memory.
13 when you restart the computer after adding or removing dimms, the computer displays a message that the memory configuration has changed.
complete the following steps to install a pair of dimms:
1. read the safety information beginning on page vii, and the guidelines in “handling static-sensitive devices” on page 33.
2. turn off the computer and all attached devices (see “turning off the computer” on page 19); then, disconnect all external cables and power cords.
3. remove the side cover (see “removing the side cover” on page 37).
4. remove the support bracket (see “removing and installing the support bracket” on page 38).
5. for easier access to the memory modules on the system board, rotate the drive cage out of the computer until it locks into place. you might need to disconnect the power cables from the drives before you rotate the cage all the way.
if you are installing memory modules on the microprocessor board for a second microprocessor on the computer, it is not necessary to move the drive cage.
6. if you are installing dimms for microprocessor 1, and you have installed a second microprocessor on the computer, remove the microprocessor 2 air baffle:
a. lift up on the large end of the baffle until it releases.
b. slide the baffle toward the front of the computer; then, lift the baffle out of the computer.
7. locate the dimm connectors. determine the connectors into which you will install the dimms. see the notes on page 54 for the installation sequence.
8. gently open the retaining clips on each end of the dimm connectors you have selected and, if necessary, remove any existing dimms.
9. touch the static-protective package containing the new dimm to any unpainted metal surface on the computer. then, remove the new dimm from the package.
10. turn the dimm so that the contacts align correctly with the connector.
11. insert the dimm into the connector. firmly press the dimm straight down into the connector by applying pressure on both ends of the dimm simultaneously. the retaining clips snap into the locked position when the dimm is firmly seated in the connector. if there is a gap between the dimm and the retaining clips, the dimm has not been correctly installed. open the retaining clips, remove the dimm, and then reinsert it.
12. repeat steps 8 through 11 for the second dimm in the pair.
13. if you have other options to install or remove, do so now.
14. if you moved the drive cage out of the way in step 5, push the drive cage outward and press in on the drive-cage release tab. rotate the cage part-way into the computer, reconnect any power cables you disconnected from the drives, and rotate the cage the rest of the way back into the computer.
15. if you removed the air baffle for the optional second microprocessor in step 6, replace the air baffle.
16. replace the support bracket (see “removing and installing the support bracket” on page 38).
17. replace the side cover (see “replacing the side cover” on page 63).
18. reconnect the external cables and power cords. turn on the attached devices, and turn on the computer.