Compaq 112726-001 - ProLiant - 6500 Technology Brief page 4

Pentium II Xeon (Slot 2
cartridge)
Pentium II (Slot 1 cartridge.
ECG078/0698
T B
ECHNOLOGY RIEF
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Larger Cache Sizes
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The Pentium II Xeon processor supports larger L2 caches than previous Intel processors.
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Pentium II Xeon processors are initially available in 512-KB and 1-MB configurations with future
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plans for a 2-MB cache. In contrast, the Pentium Pro processor has a maximum 1-MB cache.
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The larger data cache provides a significant performance boost, especially in symmetric
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multiprocessing (SMP) configurations and systems used in memory-intensive applications, such
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as on-line transaction processing.
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Full-Speed L2 Cache Bus
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Previous Pentium II processors have a half-speed L2 cache bus that connects the cache memory
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and the central processing unit (CPU) core. This means a 266-MHz Pentium II actually transfers
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data between the L2 cache and CPU core at 133 MHz. In contrast, the Pentium II Xeon processor
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has a full-speed cache bus, which means that a 400-MHz Pentium II Xeon processor transfers
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data between the L2 cache and processor core at a full 400 MHz. The combination of the full-
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speed cache bus and the larger cache size greatly enhances the performance of the Pentium II
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Xeon processor relative to the Pentium Pro and previous Pentium II processors, especially in
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. . larger SMP configurations and memory-intensive applications.
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Slot 2 Cartridge
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Pentium II processors are packaged in a single edge contact (SEC) cartridge. The SEC cartridge
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for a Pentium II processor inserts into the Slot 1 connector on the motherboard, while the Pentium
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. . II Xeon's SEC cartridge inserts into the Slot 2 connector. The form factor of the Slot 2 cartridge
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is larger than that of the Slot 1. Compared with the Slot 1 cartridge, the Slot 2 cartridge has
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More pins (330 pins versus 242 pins for the Slot 1).
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Support for a four-processor multiprocessing bus.
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Load and signal integrity modifications.
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The ability to deliver more power to support the larger, full-speed L2 cache.
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The larger cartridge and corresponding motherboard connector for the Pentium II Xeon processor
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require more pins. The additional pins on the Slot 2 cartridge provide support for a four-
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processor (4P) multiprocessing system bus. Load and signal integrity modifications in the new
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design allow a Pentium II Xeon processor to drive up to four main loads on the AGTL+ bus—
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three other processors and a memory and I/O controller. This allows the Pentium II Xeon to scale
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to 4P configurations. The extra pins also provide the additional power and ground connections
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needed to support the larger, full-speed L2 cache.
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64-GB Cacheable Address Space
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The Pentium II Xeon processor is able to access up to 64 GB of RAM; however, the memory
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controller chipset determines the actual size of supported memory. Initial Pentium II Xeon
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chipsets support memory configurations up to 8 GB.
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MMX Technology
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The Pentium II Xeon processor supports MMX instructions, which allow certain applications to
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. . operate on multiple data locations with a single instruction call to the processor. The MMX
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functions are primarily used in multimedia applications such as audio and video manipulation;
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however, increasing numbers of specialized business applications are being written to take
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advantage of MMX capabilities.
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(cont.)