Dell and Compaq: A tale of two chip sets
Compaq’s ProLiant DL-580 is built around ServerWorks’ Grand Champion-HE chip set. This silicon links the DL-580’s processors to each other, to memory, and to I/O devices. Compaq’s chip-set choice creates a lower performance ceiling in a system populated with one or two Xeon processors. The system’s top CPU speed of 1.6GHz, its PC1600 DDR (double data rate) memory, and its 100MHz, 64-bit PCI-X expansion slots lag behind the specs of the Intel chip set in Dell’s system. But the Compaq makes up the performance difference with greater manageability. The DL-580’s exceptional, secure “lights out” system management meets the most demanding requirements. An optional second memory card activates ServerWorks’ memory mirroring and hot-replacement capabilities, allowing a system to keep running through even the failure of an entire RAM module. And the DL580’s capability of scaling up to four Xeon processors — a feature not yet matched by any Intel chip set — makes up for the slower maximum speed of the CPU.
Dell’s PowerEdge 2600 uses Intel’s E7500 chip set. This dual-processor server chip set gives Dell’s server a boost with faster memory, faster processors, and faster PCI-X bus slots. Loaded with a pair of 2.4GHz Xeons and a few gigabytes of PC2100 DDR memory, the PowerEdge 2600 will undoubtedly exceed the performance expectations that most IT shops attach to dual-processor servers. More CPU megahertz, quicker memory, and a faster bus also help Intel’s HyperThreading feature take off.
HyperThreading splits the PowerEdge 2600’s two physical processors into four virtual processors. It can’t match the enterprise respectability of the DL-580 — more discrete processors are generally better, especially with ServerWorks’ strong availability features — but it should give applications a noticeable kick in responsiveness compared to non-HyperThreaded architectures. It also makes the megahertz count. Without HyperThreading enabled, Intel’s fastest Xeons are so throttled by requests for memory and I/O that an incremental rise in processor speed (even going from 1.6GHz to 2.4GHz) can have a disappointing marginal impact on application performance. HyperThreading helps smooth out the performance curve by keeping more processing inside the chip.
Dell’s PowerEdge 2600 is illustrative of E7500-based systems: They are value-priced, dual-processor Xeon servers that lead the market in price/performance. In contrast, the Compaq ProLiant DL-580 puts the emphasis on reliability. Its ServerWorks chip set allows the machine to survive hardware failures that would sideline most PC boxes and most servers in the DL-580’s price class. These systems would not normally compete with each other because the DL-580 packs four CPUs into a smaller space than Dell requires for two, but the advantages of Intel’s E7500 chip set could shift dual-processor servers into a performance class previously reserved for larger systems.
— Tom Yager
