Introduction

Intel kicked off 2002 with the introduction of the 2GHz Pentium 4, therefore it’s only fitting that they’ve ended the year with another bang in the form of the 3.06GHz Pentium 4. And say what you will about the hyper-pipelined Netburst architecture’s efficiency per clock cycle, it can’t be said that its implementation hasn’t allowed the chip manufacturer to achieve incredible clock speeds. While previous processor releases moved in steps of 66MHz, with Pentium 4 Intel has been moving in leaps of up to 200MHz!

And if our experience overclocking the 3.06GHz Pentium 4 is any indication, Intel has plenty of headroom to kick up the clock frequencies well into 2003. Not only will clock frequencies be cranked up, Intel will also introduce a faster 667MHz bus for the Pentium 4. By moving from 400MHz to 533MHz the Pentium 4 gained roughly in 5% in performance at 2.4GHz. With any luck we should see similar gains when 667MHz chips debut next year.

But that’s not the only innovation coming from Intel. From today’s 3.06GHz Pentium 4 processor and on, all of Intel’s Pentium 4 chips will support the company’s Hyper-Threading technology.

With Hyper-Threading, multiple threads of a software application can be run simultaneously on one processor. Previously, multiple CPUs would have been required to perform this task. Hyper-Threaded processors essentially trick the OS into thinking that two physical processors are present. This is accomplished by using CPU resources that are otherwise left sitting idle. For example, when memory accesses are taking place, or when a branch instruction is miss-predicted. Intel has also added new registers and other circuitry within the processor as well.

Windows XP sees two CPUs

In an ideal Hyper-Threaded scenario, one thread could be utilizing the integer resources of the processor, while a second thread is busy cranking math in the floating-point unit of the processor. But obviously such an evenly divided division of work never occurs in the real world, Intel claims performance gains in the twenty-percentile range for many applications.

Obviously this isn’t enough to outperform a system equipped with multiple processors, but when you consider the added cost of a multi-processor motherboard and the CPUs themselves, a Hyper-Threaded processor like the 3.06GHz Pentium 4 offers an extremely tempting alternative. And for everyday consumers, Hyper-Threading brings a small taste of a dual-processor system at a considerably lower cost (although we’ll discuss that in more depth on the next page). The $600+ price tag of the 3.06GHz Pentium 4 prevents us from declaring simultaneous multi-threading (the basis of which Hyper-Threading technology is based on) mainstream, but as Intel releases faster Pentium 4 processors the price of this technology will slowly drop. Lets take a look at the real world performance benefits Hyper-Threading brought us.