Gigahertz Mac Finally SPEC'd

FrkyD writes "C't magazine puplished a story with the results of a test they designed using a Mac OS X-adapted benchmark suite by the Standard Performance Evaluation Corporation (SPEC) entitled CPU2000. SPEC allows comparisons to be made within a certain framework with the Intel competition. They compared the G4/1 GHz running Mac OS X with a PIII/1 GHz (Coppermine) running Windows and Linux."

Comments

Snide comments on "supercomputer" show bias

[jdb8167]

I know people are going to claim that the SPEC marks aren't susceptible to bias but the SPEC suite only test traditional architectures. As far as I know, they don't test for SIMD vector processing like the altivec.

No one ever claimed that the FP alone on the G4 was at supercomputer status, just that the G4 in conjunction with Altivec could crunch at FLOPs at "supercomputer" speeds.

Keep in mind that OS X is hardly optimized for this kind of test. OS X has just recently reached the point where it is useful as a general purpose platform. But Apple is making a big push in the scientific computing area so I expect that you will find vast improvements in the SPEC FP suite in the future.

Re:Snide comments on "supercomputer" show bias

[Matthias Wiesmann]

As far as I understand the problem, altivec is very performant but only handles single precision floats, not doubles.

While single precision floats are largely enough for multi-media processing (filters, compression, etc...), in general, number crunching is done in double precision and the floating point tests of SEPC reflect this. You don't always need double for scientific calculations, but this is altoghter another discussion.

Maybe one day we'll see a multimedia component of SPEC or Altivec will support double precision numbers (the author even mentions this at the end of the article) but until then Altivec is out and this has nothing to do with a bias of the author.

As for OS X being optimised for this kind of stuff, we are talking applications that nearly never call the OS for anything, so the impact of OS X is probably nil. The truth is, floating point calculation is not really important for most users and both Intel and PowerPC processors are optimised for integer calculations. There was a good article about this on Ars Technica.

One reason I could see to explain the large difference lies in the compiler: there has been much more work on gcc to optimise for the Intel instruction set than for the PPC instruction set. Like most RISC processors, the performance of a PPC processor is hugely influenced by the compiler.

FYI: Good articles on P4 v G4e architecture....

[jeblucas]

For those interested, arstechnica had some great articles a while ago on the processor families and the different ways they handle instructions.

Part I.

Part II.

In case you don't read the article...

[Johnny Mnemonic]

Buried in this article is this note: and switched off the second supporting processor of the dual machines. Which means that the Dual 1Gs were only run as single Gig machines--and would therefore be much faster in the real world, so cost comparisons should be made accordingly.

Re:my own experience

[HypodermicEyes]

If I may add something... there's a long thread on exactly this subject in comp.arch right now. Look for the thread called "SPEC2k results for G4". There's some very interesting comments from people that mostly seem know what they're talking about.

Re:my own experience

[Llywelyn]

Your experience, in essence, is not the norm for mac users.

My own experience is that a 300 MHz G3 will blow a 500 MHz Pentium out of the water, thats running MacOS 9.

System configurations matter, memory matters, &c.