Sneak Peek at 800MHz FSB Performanceby Anand Lal Shimpi on March 25, 2003 7:37 PM EST
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In less than a month Intel will be introducing their 865 and 875 platforms that, among other things, will enable support for a new line of Pentium 4 processors.
As we've discussed in the past, Intel is reaching a thermal/frequency wall with the current generation 0.13-micron Northwood Pentium 4 core. It is possible to scale the Northwood core past its current 3.06GHz frequency, and in fact Intel will be doing just that with a 3.2GHz Pentium 4 in the coming months, but going much further beyond that would require more effort than is absolutely necessary given the state of the competition.
With AMD's Athlon 64 not due out for several months, it doesn't make sense for Intel to push for higher frequencies on their current manufacturing process as doing so would become fairly challenging given the thermal and power requirements of >3.2GHz clock frequencies. Instead, Intel is focusing on improving the overall performance of the Pentium 4 platform through the new chipsets we mentioned above coupled with an increase in FSB frequency.
When the first Pentium 4 was released, based on the 0.18-micron Willamette core, the NetBurst FSB ran at a 100MHz frequency and sent data 4x per clock, effectively making it a 400MHz FSB from a data rate standpoint. Shortly after Intel introduced the 0.13-micron Northwood core, the transition was made over to a 533MHz FSB; the performance boost we saw with the 533MHz FSB was more than reasonable as it, along with an increase in memory bandwidth, helped increase the Pentium 4's overall IPC by feeding more data into its pipeline.
With the 865 and 875 platforms, Intel will be enabling support for a 800MHz FSB and thus a new line of 800MHz FSB Pentium 4 CPUs also due out shortly. But what sort of performance boost should we expect out of increasing the FSB to 800MHz? That's exactly the question we're looking to answer today as we perform our first tests at 800MHz.