Intel iMacs really that much faster than PPC?

Discussion in 'Mac Pro' started by macphisto, Jan 11, 2006.

  1. macphisto macrumors regular

    Jun 29, 2002
    At home
    Okay, so I was mulling this idea and let me know what you think.

    Apples to apples (no pun intended...well, maybe a little) it seems to me that the Intel chips are on par horsepower-wise with with current G5 PPC chip iMacs. The only benefit that you get with the Intel iMac is the fact that it is a dual processor iMac with a slightly faster chipset and a few other bells and whistles.

    Am I thinking correctly with this?
  2. crazzyeddie macrumors 68030


    Dec 7, 2002
    Florida, USA
    Usually, a Pentium M (single processor mobile chip) would perform better per clock than a G4, which performs better per clock than a G5. Since the Core Duo is two chips, it should perform even better... but only benchmarks will show for certain.
  3. bugfaceuk macrumors 6502


    Nov 10, 2005
    Well you know, those stats were largely bull shoe.

    They were integer and float operation through put, and the base line for equivalence would be 2x faster. I mean you would hope that with two cores, you could do approaching 2x as much (yes yes, approaching). Of course, if it (or the CPU intensive operation) is single threaded, then we might expect similiar or possibly slower performance with 2 cores.

    What is clear that a "very good at multi-tasking" OS like OS-X will benefit greatly from dual-core CPUs to become a "very very good at multi-tasking" OS. I have a dual core windows machine and a dual core linux machine, I noticed the extra core on Linux, on XP... not so much.
  4. Little Endian macrumors 6502a

    Apr 9, 2003

    According to SPEC rates the 970MP and Intel Duo are more or less equal clock for clock.

    A single 2.5Ghz 970MP Dual core chip gets 32.3 on integer and 42.8 on Floating Point.

    A single Intel Duo Dual core chip @ 2.0Ghz gets 32.6 on interger but only 27.1 on Floating Point. SPEC scores don't translate into real world performance though but I think the G5 will perform better clock for clock and core for core until more Universal binary Apps are launched and better optimizations for the intel platform are made. Remember Apple's benches are the usual twists and they are putting Intel Duo performance with it's best foot forward, we will have to wait for more detailed benchmarks.

    Anandtech also goes into detail about PowerPC vs. X86 based raw perfromance.
  5. Morn macrumors 6502

    Oct 26, 2005
    A 2.4ghz dual cpu opteron
    SPECint_rate2000 37,5
    SPECfp_rate2000 34,4

    A single dual core 2.5ghz G5
    SPECint_rate2000 32.3
    SPECfp_rate2000 42.8

    3.2ghz Pentium D
    SPECint_rate2000 32,6
    SPECfp_rate2000 32,5

    Intel Core Duo 2ghz
    SPECint_rate2000 32.6
    SPECfp_rate2000 27.1

    To put it in perspective with other CPU's around today. (And yes the 2ghz G5 and 1.67G4 are a lot slower than all of these). And it's the opteron that tends to win in most real world tests.

    Here's what the original powermac 2ghz G5 gets.
    SPECint_rate2000 17,2
    SPECfp_rate2000 15.7
  6. maya macrumors 68040


    Oct 7, 2004
    somewhere between here and there.
    Is it my imagination or did no one notice that Steve Jobs compared a single core iMac G5 to a dual core x86 iMac. :confused:

    If that were the case, then yes the Core Duo would outperform a G5. :p

    Maybe I have to re-read and watch the keynote again, to make sure. :eek:
  7. Morn macrumors 6502

    Oct 26, 2005
  8. maya macrumors 68040


    Oct 7, 2004
    somewhere between here and there.

    Well he is comparing a dual core to a single core processor. Plus the Core Duo has 2M L2 cache, while the G5 only has 512k cache. Any processor with a 1M or larger cache will see better performance gains. ;)

    If Jobs was going to compare he should have done it with a Core Solo or something. This was just sneaky, as usual.
  9. MRU Suspended


    Aug 23, 2005
    Exactly.... Why would he compare it to a dual G5 wheh it's not in the imac?

    Same as the macbookpro compared to the G4 powerbook..

    We will see what they do with the powermac's towards summer/fall I guess. I'm hoping 2x duo core all around... That would give the performace boost all around on the powermac models..
  10. Morn macrumors 6502

    Oct 26, 2005
    The powermacs won't have Core Duo.
    Conroe will be in the powermac most likely. Which will be necessary as the Core Duo is not faster than the 2.5ghz dual core G5. And we can pretty much guess from intel's estimated launch date that it's going to be out after the wwdc.
  11. AtHomeBoy_2000 macrumors 6502a


    Feb 3, 2005
    I totally agree. A lot of people forget about that part.
  12. macrumors newbie

    Jan 21, 2005

    Apple's web site has some more numbers comparing the 1.83 dual core MacBook with the 1.67 PowerBook:

    3D rendering 4.1X faster
    Gaming 2.2X faster
    HTML load 1.9X faster

    So not everything is 4 to 5 times faster. I wonder how much of the speed increase is due to the faster bus.

    See for above numbers.
  13. Koodauw macrumors 68040


    Nov 17, 2003
    What I would like to see is how much faster is it for everyday apps. Floating point and integer operations mean very little to me. Does it help on the load time of apps? Does Photoshop render faster? Will safari be faster? Will it perform better with 8 apps open? 10-12? than its PPC counterpart? These are true tests of speed if you ask me.
  14. Morn macrumors 6502

    Oct 26, 2005
    Gaming? That'll be like 80% due to the faster graphics chip. Games don't yet take advantage of multiple cores.
    Koodauw, yes, if the apps are native. Though loading time is hard drive speed dependant. I think that safari and photoshop (when it's universal) will be much faster. Multitasking performance shouldn't change that much, it's mainly about ram.
  15. maya macrumors 68040


    Oct 7, 2004
    somewhere between here and there.
    You are also comparing 5 year old technology to current technology. The G4 has been out since 1999+, while the Core Duo has been out since late 2005.

    Of course the Core Duo will outperform on the notebook side, and also the desktop side, as the G5 was released mid 2003.

    One has to remember that you cannot compare directly a G5 or G4 with a Core Duo unless you have a dual core G4 or G5 in the same cat.

    Sure the Core Duo does more work per watt, however that is expected as its considered new technology. Its all marketing. ;)
  16. andiwm2003 macrumors 601


    Mar 29, 2004
    Boston, MA

    the only relevant measure is how much faster my apps are on the new mac compared to the old mac. if the new mac has 2,4,8 cores and the old mac has only 1 core doesn't matter at all.

    theoretical comparisons of a non existant single core 1mb cache g5 powermac to a nonexistent intel core duo single 1mb cache are a waste of time.

    performance of the apps is important to the user not techical justifications why the old mac is slower. who cares?
  17. Flowbee macrumors 68030


    Dec 27, 2002
    Alameda, CA
    And yet, until this week, Apple was selling the G4 Powerbooks as "current" technology.
  18. Morn macrumors 6502

    Oct 26, 2005
    The Core Duo is based on the Pentium Pro which was out in 1995. Although it's been tweaked an awful lot since then. :) The G4 is just a G3 with an added altivec unit. And the G5 is very similar with tweaks and additions, like an extra FPU unit.
    The newest microarchitectures around today, the Athlon. And the Pentium 4 which Intel is giving up. New is not necessarily better.
    And the G5 is faster than the Core Duo. But the G4 was even slower than the Pentium M, Freescale was not able to keep up with Intel.
  19. neocell macrumors 65816


    May 23, 2005
    Great White North
    Completely agree. Who the hell cares about hypothetical situations/configurations. Open the box, boot it up and which one is faster. Don't care what's inside, just how well does it work and how fast does it go. It's perfectly fair to compare the PowerBook to the MacBook and the intel iMac to the old one. What are they replacing? The old ones. What are you doing? Buying a new one and using it? Crap, how could anyone bitch about this. Is it faster, yes or no, if so how much. Period.
  20. Meyvn macrumors 6502

    Feb 3, 2005
    It's also fairly significant that the G5 is 64-bit, and this first generation of Core Duos are not.
  21. lssmit02 macrumors 6502

    Mar 25, 2004
    Yeah, I was wondering about that. Most apps don't benefit from the G5 being a 64 bit processor, in OS X, though,

    According to Apple

    But the same might not be true with a 32-bit Core Duo.
  22. Meyvn macrumors 6502

    Feb 3, 2005
    I never bought the 64-bit on 64-bit is a huge difference over 32-bit on 32-bit anyway. What I was arguing is: what happens when significant applications begin to be released in only 64-bit format? What happens when significant features in future OS releases and applications (which is more probable than simply completely disabling 32-bit support any time soon) are only available for 64-bit computers? THAT is the real concern.
  23. Morn macrumors 6502

    Oct 26, 2005
    64bit is mostly hype, it doesn't make much different in 90% of apps
  24. Catfish_Man macrumors 68030


    Sep 13, 2001
    Portland, OR
    The G5 is almost totally unrelated to the G4. All it shares is the instruction set (including Altivec). Different number and types of execution units, different pipeline lengths, cacheline size, out of order depth, number of rename registers, dispatch width, bus type and speed, basically everything. The G5 is descended from the POWER4 line, not the G3 line.

    One thing I've been wondering is this:
    Why does the 970MP (dual core G5) score SO much better on SPECcpu (which is single threaded) than the 970FX does?

    I believe that the key point is that it used version 8 of IBM's compiler, rather than version 6 as the 970FX did. XlC 8 can automatically multithread and vectorize programs in certain situations, so what claims to be a single threaded non-vector benchmark may have ended up being a dual threaded vector benchmark, at least to a certain extent, allowing the 970MP to use some of its second core to help the first core out.

    For reference:
    2.5GHz 970MP SPECint: 1428
    2.5GHz 970MP SPECfp: 2076
    2.2GHz 970FX SPECint:1040
    2.2GHz 970FX SPECfp: 1241
    2.26GHz Pentium-M SPECint: 1839
    2.26GHz Pentium-M SPECfp: 1375

    note: Pentium-M here refers to Dothan, which is the predecessor to the Core Duo (Yonah).


    in response to the 64 bit posts: the main point of 64 bit is to allow for more than 4GB of ram.

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