Compaq DC7600 HP Compaq dx 7200 and dc7600 Personal Computers, Technical Refer - Page 49

Processor/Memory Subsystem Figure 3-2 illustrates the internal architecture of the Intel Pentium 4 processor. Pentium 4 Processor Branch Prediction 16-K Execution Trace Cache CPU Rapid Exe. Eng. ALUs Out-of-Order Core 128-bit Integer FPU FSB I/F 8-K L11 CDaacthae Cache L2 Adv.. Transfer Cache Core speed ALU Speed (Core speed x2) FSB speed (max. data transfer rate) Pentium Type P4 670 P4 660 P4 650 P4 640 P4 630 Core Speed 3.80 GHz 3.60 GHz 3.40 GHz 3.20 GHz 3.00 GHz ALU Speed 7.6 GHz 7.2 GHz 6.8 GHz 6.4 GHz 6.0 GHz FSB Speed 800 MHz 800 MHz 800 MHz 800 MHz 800 MHz L2 Cache Size 1 MB 1 MB 1 MB 1 MB 1 MB Figure 3-2. Pentium 4 Processor Internal Architecture The Intel Pentium 4 increases processing speed by using higher clock speeds with hyper-pipelined technology, therefore handling significantly more instructions at a time. The Pentium 4 features a branch prediction mechanism improved with the addition of an execution trace cache and a refined prediction algorithm. The execution trace cache can store 12 kilobytes of micro-ops (decoded instructions dealing with branching sequences) that are checked when re-occurring branches are processed. Code that is not executed (bypassed) is no longer stored in the L1 cache as was the case in the Pentium III. The front side bus (FSB) of the Pentium 4 uses a 200-MHz clock but provides bi- and quad-pumped transfers through the use of 2x- and 4x-MHz strobes. The Pentium 4 processor is compatible with software written for x86 processors. 3.2.2 Processor Upgrading All models use the LGA775 ZIF (Socket T) mounting socket. These systems require that the processor use an integrated heatsink/fan assembly. A replacement processor must use the same type heatsink/fan assembly as the original to ensure proper cooling. The processor uses a PLGA775 package consisting of the processor die mounted "upside down" on a PC board. This arrangement allows the heat sink to come in direct contact with the processor die. The heat sink and attachment clip are specially designed provide maximum heat transfer from the processor component. Ä CAUTION: Attachment of the heatsink to the processor is critical on these systems. Improper attachment of the heatsink will likely result in a thermal condition. Although the system is designed to detect thermal conditions and automatically shut down, such a condition could still result in damage to the processor component. Refer to the applicable Service Reference Guide for processor installation instructions. Ä CAUTION: Installing a processor that is not supported by the system board may cause damage to the system board and/or the processor. Technical Reference Guide www.hp.com 3-3