Single CPU in Dual Operation: P4 3.06 GHz with Hyper-Threading Technology

Summary: In Some Cases The P4 3.0HT Can Even Beat The 3.6 GHz Version

We have been comparing the new 3.06 P4 with a CPU that is not officially available - the P4 3.6 GHz. Additionally, we have disabled Hyper-Threading at 3.06 GHz to show the performance difference between P4s, with and without HT, at the same clock speed. Sysmark is the only benchmark that clearly shows the advantage of Hyper-Threading at the moment. In other test apps the increase in speed is less substantial. The reason for this can be explained quite easily. Sysmark uses several applications simultaneously during a benchmark session. It imitates the behavior of a standard user pretty well, and the entire philosophy behind Hyper-Threading is best suited to this type of scenario. In some benchmarks the picture looks different. We realized that HT can even slow down the CPU a little bit. In single-threaded applications, the HT version of the P4 shows weaknesses when a cache thrash condition occurs.

In real world situations the feel of Hyper-Threading is much better that our benchmarks actually show; this is why we also produced the video, which demonstrates this. Hyper-Threading is particularly beneficial when at least two applications are making heavy demands on the processor simultaneously. This can easily occur when you are archiving large amounts of data in the background, while working with your standard office applications in the foreground. Similarly, MPEG-4 encoding of a DVD film can be carried out, while at the same time e-mails can be edited with several browser windows open. One important conclusion for all hardware test magazines is that everyone must re-think test methodologies. Running just a single-threaded benchmark on its own does not represent real-world behavior anymore. THG has started working on this issue already, and our video gives you a little taste of what's to come.

Let's look at the situation from an overall perspective: with the introduction of the 3.06 GHz P4, Intel has distanced itself from the competition at AMD, still unable to supply its top model, the XP 2800+. In practical terms, this means that the XP 2600+ (2133 MHz) is the AMD product competing with the P4 3066 (3.06 GHz). The Athlon 2800+ was only able to match the 3.06 GHz P4 in a few areas: 3D rendering, Cinema 4D and SPECviewperf. The difference is particularly apparent with Sysmark 2002. Advanced users should note that the Athlon XP 2800+ only approaches the performance of the 2.8 GHz P4 when the Dual-DDR333 platform is used.

With the introduction of its Hyper-Threading technology, Intel has confirmed that constantly increasing the clock cycle is not the only way to skin the proverbial cat. In simple terms, Hyper-Threading means that the P4 processor is divided internally into two virtual CPUs, and recognized as a multi-processor configuration by the operating system. But watch out! If you want to use Hyper-Threading you need an operating system that actually supports multi-processor environments, such as Windows XP. Older versions like Windows 98 or ME will only recognize the new P4 as a standard CPU without HT.