Intel Foster sneak preview

One look at the pricewatch tells us that every Xeon is a lot more expensive than its Pentium III equivalent, and the Slot 2 mainboards don’t come in cheap either. But what exactly is the difference between the two? Actually, the differences between the two have decreased over time. The original Pentium Pro had a new core and was the first processor with an in-package, full-speed L2 cache, and a lot of it too; you could buy them with up to 2MB cache. The Pentium had a maximum of 512KB cache located on the motherboard and used the same clock speed as the FSB. The Pentium II also had 512KB, but it only ran at half the speed of the processor. The Xeon has always had full-speed cache, and was also the first Intel processor able to address 64GB of memory, 16 times as much as its desktop equivalents.

This made the Xeon the perfect processor for some heavy tasks, where the
most important advantage of it was very clear; the Xeon was the only
Intel-chip that could be used in a 4-way, or even bigger, SMP system. Because of the high prices of RISC chips, the possibility to make relatively low-cost but powerful x86 systems was a solution for many companies. The Xeon also had ECC features and hardware monitoring functions. Despite the – for us mortals, that is – high cost of the Xeon, the buyers where very glad with the introduction of it.


The release of the 0.18 micron Pentium III Coppermine changed the situation. This core gave every home-user on-die full-speed L2 cache. A feature previously found only in the expensive Xeons. Furthermore, Intel created a distinction between ‘light’ and ‘heavy’ Xeons. The light ones were equipped with only 256KB of L2 cache, just like the normal Coppermine, and couldn’t be used in an SMP system. The advantages of using a light Xeon over a normal Pentium III became minimal, and the prices reflect that; the pricing of the light Xeons is closer to that of desktop processors than ever before. The heavy Xeons still exist, but there aren’t many of them. If you would like to build a 4-way system, for example, until recently, you only had the choice of the 550MHz and 700MHz versions, both only available with 1 or 2MB cache. The recently announced 900MHz version is only available with a 2MB cache.

This strategy won’t change a lot with the release of Foster, but Intel did put a little more effort in giving the light version its own place. Alas, this has an unfortunate consequence for the Pentium 4, which isn’t able to run in an SMP-configuration. If you want a dual processor system based on the Pentium 4 core, you’ll have to buy a pair of Foster DP’s. DP stands, of course, for Dual Processor, and that means that you can’t have more than two of them in one system. Companies who don’t think that that is enough, will have to buy the more expensive MP (Multi-Processor) versions. The MP’s also distinguish themselves from the DP’s by a maximum of 4MB full-speed L3 cache.

We can only speculate about the exact amounts of L2 and L3 cache in the different versions of Foster. We only know that the first available DP models will have 256kb of L2 cache. The MP version is mostly named with 512KB or 1MB L3 cache. This cache memory has to provide a better performance in applications that use the same data many times, like databases. The cache memory can also hide a part of the system memory latency, something that really comes in handy when dealing with RDRAM. The original Pentium 4 design had an L3 cache too, but this has been scrapped because of its high cost, something that is of less importance in the market for server processors.

According to the latest rumours, the DP version of Foster will be released on the 8th of may, at the same frequency range as the Pentium 4; 1,3GHz to 1,7GHz. The heavier models will make their debut a couple of months later and will be only available at 1,4GHz when they are just released. At this moment, three chipsets with support for 4 Fosters have been announced: Intel 870, ServerWorks Grand Champion and IBM Summit.


Aside from the option of more cache and SMP, a leaked Powerpoint presentation from Intel pointed us to another interesting feature of Foster. At the sheet below, you can see that ‘Jackson Technology’ is mentioned, with the caption ‘On-Chip multi-threading support’. According to some sources, Jackson Technology is an incarnation of SMT (Simultaneous Multi-Threading).