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.