X-bit labs

Windows XP Professional x64 Edition Preview: AMD64 and Intel Extended Memory 64 Technology (page 10)

Category: CPU

by Ilya Gavrichenkov

[ 02/08/2005 | 02:16 PM ]

Now let’s take a look at the performance of our testing participants in other applications. One of the few real-life programs available for 32-bit as well as 64-bit mode is the PovRay 3.6 rendering system. We used the integrated benchmark to test the performance of our Pentium 4 processor supporting EM64T and Athlon 64 processor in Windows XP Professional x64 Edition (the higher score on the diagram indicates better result):

Here we see a completely different situation than the results of SiSoft Sandra 2005 SP1. Athlon 64 processor runs 25% faster with 64-bit AMD64 extensions involved than in 32-bit mode. Intel Pentium 4 with EM64T, on the contrary, loses about 25% of its speed in 64-bit mode.

The next benchmark we used for our performance investigation of Intel and AMD CPUs is a small Pi-Bench program, which calculates the pi-number as a sum of a series. The diagram below shows how long it took to complete this calculation with the given precision value.

In this case we see that 64-bit mode appears favorable for Athlon 64 as well as Pentium 4 with EM64T. However, the performance increase of Athlon 64 processor in 64-bit mode is a bit higher and equals 55%, while Pentium 4 managed to benefit by only 35% of extra performance.

One more task we are going to use today for benchmarking purposes is test file compression according to the zip-algorithm using zlib library. The diagram below shows how much time it took our testing participants to finish the task.

Again we witness a significant performance boost when we use the execution code optimized for 64-bit extensions of AMD64 and EM64T. In this case the performance increase by the CPU with AMD64 technology made 120%, while in case of a CPU with Intel EM64T technology the performance in 64-bit mode grew up by 65%. In other words, we once again see that AMD’s implementation of 64-bit extensions appeared more efficient than 64-bit extensions for x86 architecture from Intel.