Yfel#24
Ezt az Apple Rajongóknak akik annyira szeretik az x86 architektúrát
That puts Apple's figures in a new light. On one hand we have figures that suggest the 2GHz G5 outperforms the 3GHz Xeon in certain benchtests, and on the other we have numbers that show the exact opposite. What gives?
Firstly, Dell's own figures were calculated using different compilers and host operating system: Windows XP Pro, Intel's own C++ and Fortran compilers, and the MicroQuill SmartHeap Library 6.01. Secondly, the compiler used by VeriTest, GCC, is said to generate code that less well optimised for x86. Thirdly, VeriTest seems to have adjusted the test hardware to favour the G5. Again, all the details are there in the documentation.
VeriTest admits it used an Apple-supplied tool to adjust the G5 processor's registers "to enable Memory Read Bypass" and "to enable the maximum of eight hardware prefetch streams and disable software-based pre-fetching". The company also installed a "high performance, single-threaded malloc library... geared for speed rather than memory efficiency". That, says VeriTest, "makes it unsuitable for many uses".
We'd guess these are hardly standard system configurations.
VeriTest also says it tweaked the Dell boxes. For example, when it came to the SPECint and SPECfp rate tests, it disabled HyperThreading, though enabled it for the base SPECint and SPECfp tests. While the compilers were set to optimise code for the Pentium 4, SSE 2 instructions were not used to speed floating point maths operations, only SSE 1 instructions were enabled. VeriTest provides no clear rationale for these choices