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Besides the thermal tests, we also checked the overclocking potential of the new Prescott CPU. This experiment will give us some idea of the frequency potential in C0 core stepping of the new Prescott processors. For our tests we took Pentium 4 (Prescott) with the nominal frequency of 3.2GHz. We didn’t use any special cooling solutions, besides a traditional boxed cooler. Top achieve better results we increased the processor Vcore to 1.475V.

During our overclocking experiments we managed to raise the FSB frequency from the nominal 200MHz to 225MHz, so that the CPU got overclocked to 3.6GHz.

I wouldn’t call this result impressive. Especially taking into account that Intel claims the frequency potential of up to 4.5GHz. But note that this is only one of the very first core steppings. As the manufacturing technology improves, ongoing core revisions designed for LGA 775 Prescott versions will boast much higher overclocking potential, for sure.

Besides, I should also say that we could have achieved better results during our overclocking attempts if we had used some more advanced cooling solutions. When the CPU worked at 3.6GHz it warmed up to 68-70oC. The maximum Tcase temperature for Prescott based CPUs makes 73.5oC. This way there is no doubt that overclocking was limited by the fast growing temperature of the processor core. So, some extreme overclocking fans, who have water cooling or cryogen cooling systems at their disposal, will be able to squeeze much more MHz out of their Prescott based CPUs.

A Bit of Performance Tests

Winding up our introductory article to the new Intel Prescott processor core and its features we decided to run a few benchmarks, which will give you some idea about the performance of the CPUs based on the new core. We took a popular SiSoft Sandra 2004 test package, because it contains a few simple algorithms, which can involve or not different functional units of the processor upon the user’s request. Besides, these tests are so simple that they do not depend on the size and performance of the L2 cache-memory as well as on the efficiency of the memory subsystem. In other words, other system components do not impose any influence on the CPU performance during the tests.

We will test Pentium 4 (Prescott) and Pentium 4 (Northwood) working at 3.2GHz core frequency. The table below contains the results obtained in SiSoft Sandra 2004 measuring the processor performance when building the Mandelbrot set:

 

Pentium 4 (Northwood)

Pentium 4 (Prescott)

Hyper-Threading Enabled

Hyper-Threading Disabled

Hyper-Threading Enabled

Hyper-Threading Disabled

Integer SSE2

24520

19890

22637

18114

Float SSE2

35492

23542

30468

20693

Integer SSE

19923

17674

19480

16756

Float SSE

33280

24764

29260

20843

Integer MMX

14791

13158

14877

12481

Float FPU

6470

3281

5780

2966

Integer ALU

9198

7101

16033

11686

We will not perform any indepth analysis of these results, as they are mostly intended to give us a general idea of the CPU performance. We will discuss the performance of the new Prescott based processor in a different article, where you will see the whole bunch of tests. Here I would only like to say that the performance of Prescott’s functional units responsible for FP/MMX/SSE/SSE2 instructions didn’t get any better compared with Northwood. Lower results obtained for FP/MMX/SSE/SSE2 unit of the Prescott processor were caused by higher L1 cache latency in the first place. Note that Prescott’s performance with ALU’s involved is higher than the performance of a Northwood based processor in the same test. This victory can be explained by the above described architectural enhancements, namely faster multiplication processing, which is essential during Mandelbrot set calculations.

 
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