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Author Topic: PPC vs x86 speed/performance comparions?  (Read 11190 times)

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Re: PPC vs x86 speed/performance comparions?
« on: February 02, 2008, 02:34:47 AM »
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mingle wrote:
Okay, I understand that MHz isn't a good benchmark...

What I'm getting at is how they compare, ie: MIPs/ Dhrystones/ Real World performance...

If I have a 1.8GHz G5 Mac and a 2.0GHz P4, running the same OS (Say a flavour of Linux), which would yield better performance?


The P4 is pretty lame... The G5 will be at least as fast if not quite a bit faster... If you had an Athlon64 or a CoreDuo then they would piss all over the G5 :-)

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Re: PPC vs x86 speed/performance comparions?
« Reply #1 on: February 11, 2008, 02:13:57 PM »
Well, I have both a Athlon64 3200 (Which I think is 2.2Ghz) and a PPC 7447A (ie a 1.5Ghz G4 in my old Mac)... I can confirm that the G4 is about as half as fast in every operation as the Athlon64. Which is what one would expect. Pretty much all my tests are based on using Logic Pro...

If someone has any cross platform benchmarking tools they would like me to run, I would be happy to and will publish the results. (I also have a 3Ghz P4 as well)

The 2.4Ghz Core2Duo in my MacBook Pro... out classes all of those other machines!


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Re: PPC vs x86 speed/performance comparions?
« Reply #2 on: February 11, 2008, 02:31:47 PM »
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Agafaster wrote:
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JJ wrote:
You cant even compare different genrations of the same  processor family by MHZ.  MHZ is the most pointless indicator of chip performace of chips thers is. Unless you are comparing chips of eexactly the same architecture.  Obivously 50mhz 030 is faster than a 25mhz 030.  But you cant compare it against anything else by the MHZ


Although saying that, I do recall a 'rule of thumb' that a PPC of a certain clock could perform around 2x the equivalently clocked contemporary Pentium. I guess that'd be the PIII cf. the G3 though...



No, that would be against the Pentium4 which had very long (22 stage?) pipelines, so that very high clock speeds could be achieved, at the expense of work that could be done per clock cycle. It was a strategy based on the idea that transistor switching speeds would increase dramatically in a short space of time... this did not happen and they have currently topped out at around ~3Ghz.

AMD and Motorola opted for shorter pipelines, which resulted in lower clock speeds but more work gets done per cycle... With the Core2 architecture Intel have adopted the same approach, and brought with them all the good stuff from the P4 (ie great branch predictors and macroop fusion, etc)... (and borrowed all the good ideas of the Athlon64 and the PIII too)...


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Re: PPC vs x86 speed/performance comparions?
« Reply #3 on: February 11, 2008, 02:48:56 PM »
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downix wrote:
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bloodline wrote:
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Agafaster wrote:
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JJ wrote:
You cant even compare different genrations of the same  processor family by MHZ.  MHZ is the most pointless indicator of chip performace of chips thers is. Unless you are comparing chips of eexactly the same architecture.  Obivously 50mhz 030 is faster than a 25mhz 030.  But you cant compare it against anything else by the MHZ


Although saying that, I do recall a 'rule of thumb' that a PPC of a certain clock could perform around 2x the equivalently clocked contemporary Pentium. I guess that'd be the PIII cf. the G3 though...



No, that would be against the Pentium4 which had very long (22 stage?) pipelines, so that very high clock speeds could be achieved, at the expense of work that could be done per clock cycle. It was a strategy based on the idea that transistor switching speeds would increase dramatically in a short space of time... this did not happen and they have currently topped out at around ~3Ghz.

AMD and Motorola opted for shorter pipelines, which resulted in lower clock speeds but more work gets done per cycle... With the Core2 architecture Intel have adopted the same approach, and brought with them all the good stuff from the P4 (ie great branch predictors and macroop fusion, etc)... (and borrowed all the good ideas of the Athlon64 and the PIII too)...


With the irony being that Intel's next-gen chips are going back to the classic P4 methodology...


Well... err... only as far as I can see... The silverthorn, with its simple in order pipeline... but that is with good reason, i.e. to get a small die and low power consumption so it can compete with the ARM...

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Re: PPC vs x86 speed/performance comparions?
« Reply #4 on: February 11, 2008, 05:16:18 PM »
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StormLord wrote:
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If someone has any cross platform benchmarking tools they would like me to run, I would be happy to and will publish the results. (I also have a 3Ghz P4 as well


even crossplatform benchmarking can't show the real difference and that because most of them are optimised and builted for one type of machines and just crossed compiled to the other, instead of rewriting the program from scratch to take care different architectures.. also different architectures can have very different results in different tests
Example: try to run distributed net OGR to that single 1.5Ghz G4 and OGR on that 3200AMD, both cores are written from scratch for the specific CPUs , results:
G4 will be about 3-4x faster than the athlon, but that is not true in everyday tasks performance


Which is why I based my statement upon running Logic Pro (called Logic Platinium at the time) on both machines... running 8 tracks on both, and then loading up the effects inserts.

I was a bit gutted at the time, as the Mac had cost me a small fortune... the Athlon64 components didn't cost more than £300 in total including 1 Gig or ram...