HP 355856-001 manual Single Channel and Dual Channel Modes

Hardware Upgrades

■contain the mandatory JEDEC SPD information In addition, the computer supports:

■128Mbit, 256Mbit, and 512Mbit non-ECC memory technologies

■single-sided and double-sided DIMMS

■DIMMs constructed with x8 and x16 DDR devices; DIMMs constructed with x4 SDRAM are not supported

Maximum operating speed is determined by a combination of the CPU and type of memory used. Refer to the table below for the optimum combination.

Maximum Front Side Bus Operating Speed (MHz)

CPU Front Side Bus	DDR266	DDR333	DDR400
(MHz)	DIMM	DIMM	DIMM
400	266	266	266
533	266	333	333
800 (d248 only)	266	320	400

✎The system will not start if you install unsupported DIMMs.

Single Channel and Dual Channel Modes

HP Compaq d228 and d230 Microtower models operate in single channel mode. HP Compaq d248 Microtower models will automatically operate in single channel mode or a higher-performing dual channel mode, depending on how the DIMMs are installed.

■In single channel mode, the maximum operational speed is determined by the slowest DIMM in the system. For example, if the system is populated with a DIMM that is 266 MHz and a second DIMM that is 333 MHz, the system will run at the slower of the two speeds.

■In dual channel mode (d248 models only), all DIMMs must be identically matched. DIMMs in the J23 and J24 sockets must be identical; DIMMs in the J25 and J28 sockets must also be

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