A guy over at the Comp.arch newsgroup has managed to speed up a AMD Athlon FX51 by 22% in SPEC CPU2000, using Intel compilers version 8.0 that he download for free from Intel! Here's a snip.
First I wanted to pick a primarily CPU-bound test to run, so I chose SPEC CPU2000. The test system was a P4 3.2G Extreme Edition with 1 gig of ram running WIndows XP Pro. First I compiled and ran spec with the "generic x86 flag" (-QxW), which compiles code to run on any x86 processor. After running the generic version, I recompiled and ran spec with the "Intel-specific flag" (-QxN) to see what kind of difference that would make. For most benchmarks, there was not very much change, but for 181.mcf, there was a win of almost 22% ! Curious as to what sort of optimizations the compiler was doing to allow the Intel-specific version to run 22% faster, I tried running the same binary on my friend's computer. His computer, the second test machine, was an AMD FX51, also with 1 gig of ram, running Windows XP Pro. First I ran the "generic x86" binaries on the FX51, and then tried to run the "Intel-only" binaries. The Intel-specific ones printed out an error message saying that the processor was not supported and exited. This wasn't very helpful, was it true that only Intel processors could take advantage of this performance boost?
Intel Compilers Speed UP Athlon FX51
First I wanted to pick a primarily CPU-bound test to run, so I chose SPEC CPU2000. The test system was a P4 3.2G Extreme Edition with 1 gig of ram running WIndows XP Pro. First I compiled and ran spec with the "generic x86 flag" (-QxW), which compiles code to run on any x86 processor. After running the generic version, I recompiled and ran spec with the "Intel-specific flag" (-QxN) to see what kind of difference that would make. For most benchmarks, there was not very much change, but for 181.mcf, there was a win of almost 22% ! Curious as to what sort of optimizations the compiler was doing to allow the Intel-specific version to run 22% faster, I tried running the same binary on my friend's computer. His computer, the second test machine, was an AMD FX51, also with 1 gig of ram, running Windows XP Pro. First I ran the "generic x86" binaries on the FX51, and then tried to run the "Intel-only" binaries. The Intel-specific ones printed out an error message saying that the processor was not supported and exited. This wasn't very helpful, was it true that only Intel processors could take advantage of this performance boost?
Intel Compilers Speed UP Athlon FX51
