 The magazine of the Melbourne PC User Group Intel's Xenon processor - Remaking the Industry? George Skarbek gskarbek@melbpc.org.au |
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After a long period between updates of Intel's top processor, the Xeon processor has finally been released. I was in Sydney for this product launch and below are my views on the Xeon. This processor is the replacement of the Pentium Pro and is aimed clearly at the Server and Work-station market, not the home/small business market. The Celeron and Pentium II processors are designed for that market.
The main feature that separates Xeon from other Intel products is that is has support for four or eight CPU computers. The Pentium II will only support two CPUs. Note that Windows 98 cannot support multiple CPUs and an operating system such as Windows NT or UNIX is required to make full use of these additional CPUs.
The Xeon runs at 400 MHz and has a 400 MHz cache bus to the large L2 cache. The L2 cache can be 512 KB or 1 MB. A Xeon with a 1 MB cache gives about 10-15% improvement over the 512 KB cache processor but costs more than twice as much. It also has cachable address space up to 64 GB, error checking and correction memory that can correct single-bit errors plus a thermal sensor that will prevent damage to the CPU due to overheating.
Ziff-Davis Benchmarks indicate that a four-processor Xeon is about three times faster than a four-processor Pentium Pro in a typical client/server environment. TPC-D benchmarks produced by Intel show that four-processor Xeon with the 1 MB L2 cache not only gives the best results but in $/TPC-D is by far the cheapest computer when comparing to a Digital Alpha, a Sun UltraSparc and an IBM RS/6000. Similar results were also shown for TPM-C benchmarks.
These benchmarks indicate Intel's direction for its high end CPU which is aimed the RISC computers that are widely used in the engineering environment. However, results of the relatively SPECweb96 (measuring Webserver performance) showed a four-CPU Xeon outperforming a 12-CPU PowerPC and an eight-CPU MIPS computer, indicating that the Xeon should be considered for heavy duty Internet applications.
The Xeon comes on a new cartridge that fits into a new and longer connector called Slot 2 in a system's motherboard. It requires a new chip set to enable it to interface with other system components. The Slot 1 used Pentium IIs to talk to their L2 cache at half the CPU's clock speed but the Slot 2 Xeon processors talk to L2 at the full clock speed. This is needed to get the data and instructions to the very fast CPU as the cycle time for the processor is 2.5 ns while the fastest RAM used is 50 ns.
Intel has also released a chipset that is optimised for the four-way Xeon processor, the 450NX PCIset. This will support up to 8 GB of 50 ns memory and has a 100 MHz bus and, not surprisingly, is the recommended chipset.
For comparison, in a single CPU computer running Windows 98, the Xeon will be only a few percent faster than the 400 MHz Pentium II because the internal L2 cache runs at 400 MHz compared to half that speed for the Pentium II. The Xeon cost, however, will be a lot more than a few percent higher.
In the presentation, Intel stated that its processor is "Remaking the Industry". I feel that their marketing people may have delusions of grandeur. In my opinion the Xeon processor represents a gradual evolution, not a quantum leap. (It will be interesting to see how its 64-bit processor will be described). The benchmarks are impressive and manufacturers such as Sun, HP, Digital may have a challenge in the workstation market until they release their next generation of processors.
Fortunately for computer users Moore's Law is not showing any signs of settling at a plateau yet. For the foreseeable future (about three to four years, but probably for much longer) computers will get faster and cheaper.
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Reprinted from the August 1998 issue of PC Update, the magazine of Melbourne PC User Group, Australia
