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AntareZ

En X-bit Labs han hecho un análisis de cómo varía el rendimiento del Core 2 Extreme X6800 en Windows XP Professional x64 Edition respecto a cómo lo hace en Windows XP Professional SP2, compárandolo con los rendimientos del Athlon 64 FX-62 y del Pentium Extreme Edition 965.
En general las variaciones de rendimiento se van alternando, los casos más destacables son según el Sisoft Sandra, el mayor aumento de rendimiento del Core 2 en cálculos en coma flotante y la caída de rendimiento el cálculos aritméticos (cuando los otros dos mejoran el rendimiento). También son interesantes los resultados del Molecular Dynamics, donde el K8 obtiene un 270% de rendimiento frente al 211% del Core 2, o el 7-Zip, en el que el Core 2 mejora el resultado y el K8 empeora.
Como media, el Athlon 64 mejora un 16% en 64 bits y el Core 2 un 10%. Por lo que no hay una diferencia tan sustancial como para cambiar las impresiones obtenidas del rendimiento en 32 bits, ya que a igual frecuencia de reloj, el Core 2 era en torno a un 20% más rápido.

Aca un resumen:

Testbed and Methods

CPUs:
- AMD Athlon 64 FX-62 (Socket AM2, 2.8GHz, 2x1024KB L2);
- Intel Core 2 Extreme X6800 (LGA775, 2.93GHz, 1067MHz FSB, 4MB L2);
- Intel Pentium Extreme Edition 965 (LGA775, 3.73GHz, 1067MHz FSB, 2x2MB).
Mainboards:
- ASUS P5W DH Deluxe (LGA775, Intel 975X Express);
- ASUS M2N32-SLI Deluxe (Socket AM2, NVIDIA nForce 590 SLI).
Memory:
- 2048MB DDR2-800 SDRAM (Mushkin XP2-6400PRO, 2 x 1024 MB, DDR2-800, 4-4-4-12).
Graphics card: PowerColor X1900 XTX 512MB (PCI-E x16).
Storage subsystem: Maxtor MaXLine III 250GB (SATA150).
OS:
- Microsoft Windows XP Professional SP2;
- Windows XP Professional x64 Edition.

The tests were performed with the mainboard BIOS setup for maximum performance.

Performance: What’s the Practical Result?

Although quite a bit of time has passed since the release of Windows XP Professional x64 Edition, the native 64-bit applications haven’t yet got that widely spread. Therefore, every time we tend to measure the 64-bit performance of x86-64 processors, we face the necessity of finding suitable applications that would allow us to measure the systems performance and that would exist in 32-bit as well as 64-bit version. Therefore, you shouldn’t be surprised that there are so few applications that we look at within this test session.

A very well-known utility that contains both: 32-bit and 64-bit code, is SiSoft Sandra 2007. Depending on the OS version, this program uses either 32-bit or 64-bit core. As a result, we could use a few small synthetic tests from the SiSoft Sandra 2007 suite to compare the performance of Core 2 Extreme X6800, Athlon 64 FX-62 and Pentium Extreme Edition 965 in 64-bit modes against their performance in 32-bit modes.

The results we obtained are very diverse, so we cannot really make any definite conclusions. Namely, the CPU with Core microarchitecture loses a lot of its speed when switching to 64-bit mode in ALU test, while Pentium Extreme Edition 965 and Athlon 64 FX-62 get slightly faster. In the arithmetic SSE3 test all CPUs work faster in the 32-bit version of the application. The only subtest showing the advantages of the 64-bit mode is Multimedia Floating Point. This is where Core 2 Extreme X6800 wins most in 64-bit mode speeding up by well over good 40%.
However, we wouldn’t really focus on these results. The thing is that 32-bit and 64-bit test versions within the SiSoftware Sandra 2007 suite use different algorithms based on different sets of instructions. Therefore, these results cannot serve as a basis for far-fetched conclusions.

Let’s take a look at the results obtained in a few other applications. We will now take ScienceMark 2.0. This test estimates the systems performance when working on typical mathematical modeling of physical processes.

The first test, Molecular Dynamics, models the thermodynamic condition of the substance using molecular dynamics methodology. As we see, the algorithms used in this case work much faster in 64-bit mode. We see the highest performance gain by the K8 processor, which gets 2.7 times faster. As for Core 2 Extreme X6800, it boasts slightly lower results, speeding up by “only” 111%.

Another scientific test, Primordia, that calculates the quantum atom structures also reveals the advantages of the 64-bit architectures over 32-bit ones. However in this case, the performance advantage is not as high as in the previous case. The maximum performance boost belongs to Pentium Extreme Edition 965 processor working 57% faster in 64-bit mode. Athlon 64 FX-62 and Core 2 Extreme X6800 receive almost identical performance boost from switching to 64-bit mode: 14%.

Thanks to the benchmarking tool built into one of the most efficient archiving utilities – 7-zip, we measured the data compression and decompression speeds for different CPU work modes. The results show that there is only one CPU that benefits from switching to 64-bit mode: it is AMD Athlon 64 FX-62. Intel processors with NetBurst as well as Core microarchitecture slow down with EM64T enabled.

During data decompression all the testing participants show some performance improvement from switching to the 64-bit mode. However, the performance of Core 2 Extreme X6800 processor improves by only 2.5% and is a way lower than the performance boost on Intel NetBurst and AMD K8 based solutions.

Video encoding into wmv-format in 64-bit mode accelerates only on systems with NetBurst based processors. As for Core 2 Extreme X6800 and Athlon 64 FX-62 they work slower in 64-bit version of the Windows Media Encoder than in the 32-bit one. The difference makes about 10%.

PDNBench is a test that reveals the system performance when working with typical image editing tasks in a popular open graphics editing suite aka Paint.NET 2.64. The results obtained in this test show a pretty significant performance boost provided by the AMD64 and EM64T extensions. According to the chart above, the CPUs get 25% to 42% faster with the maximum performance improvement available from Intel Core based CPU.

Strangely enough, but the results of the computer algebraic Mathematica test show the advantage of EM64T over AMD64. Intel processors appear slightly faster in the 64-bit application version, while Athlon 64 FX-62 slows down by 13% in 64-bit mode.

Cinebench test shows the systems performance in professional 3D modeling application – Cinema 4D, which is available for both: standard Windows XP as well as Windows XP Professional x64 Edition. The final rendering results suggest that the system built on Athlon 64 FX-62 benefit most from the 64-bit work modes. In this case it gets 13% faster. EM64T technology implemented in Core 2 Extreme X6800 and Pentium Extreme Edition 965 cannot boast the same efficiency, so Intel processors speed up by only 5%.

As for OpenGL operations, they work slower in 64-bit mode than in 32-bit mode. And the processor microarchitecture has nothing to do with it. Looks like the graphics card driver is not quite optimized yet for Windows XP Professional x64 OS. And this is one of those factors that prevent 64-bit operating systems from getting popular.

POV Ray is a quite known 3D modeling system using ray tracing methods. Just like Cinema 4D, it is available for 32-bit and 64-bit platforms. Therefore, we couldn’t miss this opportunity to test our platforms in this application. The results once again show the victory of 64-bit processors. The 64-bit rendering is faster than in case of a regular 32-bit program version. As a result, Athlon 64 FX-62 speeds up by about 14%, while Core 2 Extreme X6800 – by 4%. As for Pentium Extreme Edition 965, the 64-bit POV-Ray works slower with it than the 32-bit one.

Most contemporary 3D games supporting x86-64 use the advantages of 64-bit work modes to ensure better image quality, so they don’t suit that well for our today’s test session. Luckily, we managed to find one game that doesn’t improve the image quality in the 64-bit mode without changing the appropriate graphics settings). It is Unreal Tournament 2004, which will be our measuring tool for performance analysis with enabled 64-bit EM64T and AMD64 extensions of our testing participants.
As we see, enabled 64-bit extensions do not affect the gaming performance that much. Athlon 64 FX-62 and Core 2 Extreme X6800 get only 1-2% faster, while Pentium Extreme Edition 965 wins more: the good 9%.

Conclusion

As we have expected, nothing serious has happened. CPUs with Intel Core microarchitecture and EM64T technology work normally in 64-bit modes. No dramatic performance drop has been detected in most benchmarks.
Of course, there are a few applications, when Core 2 Duo work slower in their 64-bit versions than it would in their 32-bit ones. Among them are Windows Media Encoder 9 or 7-zip archiving tool, for instance. However, since the other testing participants have also lost some of their performance in these tasks, the problem is most likely to be not in the microarchitecture. EM64T technology of Core 2 Duo processors has a positive effect on the performance in the majority of applications.

The diagram shows the performance increase (in percents)
for CPUs with Intel Core and AMD K8 microarchitecture
when we switch from 32-bit to 64-bit applications.

At the same time I would like to point out that it looks like Athlon 64 processors ensure higher performance increase when switching to 64-bit work mode. The average performance improvement we have seen from Athlon 64 FX-62 equaled 16%, while Core 2 Extreme X6800 demonstrated only 10% average performance boost. This way, there is a certain difference: AMD K8 turns out 6% mode efficient in 64-bit mode than Intel Core. However, this difference cannot compensate for the 20% performance advantage of the Intel Core 2 Duo over the Athlon 64 X2 working at the same clock speed, which we have pointed out in our previous articles. Therefore, we will not change our conclusions about the performance of the new Intel processors even keeping in mind the upcoming launch of 64-bit Windows Vista OS family.

Saludos by AntareZ