Intel launches new processors at such a dizzying rate these days that it is becoming difficult to keep up. June 30 marked yet another processor launch for Intel: the Pentium II Xeon, which rounds out Intel’s range by providing a processor for workstation and server systems. The cost of the processor reflects its target market: Intel charges a large premium for the processor, particularly for Xeons with larger caches.
Intel is persisting with its ‘P6 core in everything’ strategy and differentiating its products through the L2 cache. The performance improvement provided by the Xeon comes primarily as a result of the increased clock speed of the cache, which now runs at the full clock speed of the processor, as opposed to the half-speed cache in the Pentium II. In some models (although not the one with which we were provided) Intel is doubling and perhaps quadrupling the size of the cache to IM or even 2M in models to appear later this year. The Xeon also incorporates Intel’s System Management Bus, which streamlines communications between the processor, thermal sensors and other system components.
The Xeon is also the first Slot 2 processor; its cartridge package is significantly larger than that of the Pentium II and requires a larger slot with a greater number of pins than the Pentium II.
The performance of the Xeon machine is difficult to evaluate. The processor itself does not provide any more raw MIPS than a Pentium II processor, but the improved cache architecture means that applications generating a lot of cache hits will sometimes have dramatically improved performance. Performance may even vary significantly across a range of products of the same type, depending on the architecture of the the software. As a result, there are as yet few general-purpose benchmarks that make use of the improved L2 cache architecture in the Xeon.
Unfortunately, without benchmarking each individual product, it’s impossible to tell whether it’s worth using a Xeon in lieu of a good old Pentium 11 processor, and we recommend that you benchmark a Xeon system with the desired applications before committing your organisation to buying one (they are rather expensive purchases, after all).
Intel claims to have the lead in the field, at least when it comes to transaction processing. The company cited performance results using SAP, the Transaction Processing Council’s TPC-C and SPECweb96 from the Standard Performance Evaluation Corporation which show the Xeon is a real player.
If you expect to find your favourite game or even workstation application dramatically speeded up, however, you may be rather disappointed. Running Ziff-Davis’Winstone 98 1.0ona400MHz Xeon machine submitted to us by Beyond Computers showed the system did have a small performance gain over the 400MHz Pentium 11 PCs we looked at a few months ago (see APC July, page 107). This was no doubt aided by the impressive specifications of the Beyond system (see sidebox).
In spite of its less than clear performance advantages, Xeon is destined to be successful, if only for the fact that it finally gives x86 server and workstation vendors an escape from using the two-year-old
Pentium Pro processor for machines with greater than two-way SMP.
At its launch, Intel announced two new chipsets for use with the Xeon processor — one for server systems and one for workstations. The workstation AGPset, the 440GX, supports dual Xeon or Pentium II processors, AGP, up to 2M of SDRAM and the 100MHz front-side bus.
The more significant release is the server chipset, the 450NX. A PCIset only (it doesn’t support AGP), the 450NX has many features that server vendors have been asking for. Designed for the Pentium II Xeon processor, the NX chipset supports up to four-way multiprocessing natively, can address up to 8G of memory and includes an enhanced I/O architecture.
It also includes support for multiple PCI buses, including 64-bit PCI buses for devices such as RAID and Gigabit Ethernet controllers, which require high bandwidth. The chipset also offers support for third-party controllers for greater than four-way multiprocessing. As a result, several of the major server vendors should be releasing six and eight-processor machines in no time.
