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NASA Benchmarks the New G5 Powermac 751

Posted by michael
from the measuring-up dept.
sockit2me9000 writes "Well NASA's Langley Research Center recently benchmarked the new G5 dual 2ghz Powermac against a dual 1ghz Xserve, a dual 1.25 ghz Powermac, a Pentium4 2 ghz, and a Pentium4 2.66 ghz. To make things fair, the second processor in the G5 was switched off, as well as the other dual sysytems. Then, they all ran Jet3d. Even with un-optimized code and one processor, the G5 performance is impressive."
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NASA Benchmarks the New G5 Powermac

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  • by CptChipJew (301983) * <michaelmiller@gm ... l.com minus city> on Friday July 04, 2003 @05:30PM (#6369191) Homepage Journal
    Because I have a strong feeling this is going to be asked:

    For those of you who were wondering, you too can switch off one of your Mac's dual CPU's with the Apple CHUD Tools [apple.com]. Look near the bottom of the page. It'll make you appreciate your second processor ;)

    Personally though, I want to see how well it runs Seti@Home [berkeley.edu].
    • by jbm (17264) * on Friday July 04, 2003 @05:50PM (#6369286)

      you ... can switch off one of your Mac's dual CPU's with the Apple CHUD Tools.

      You can also do this simply with the cpus= boot argument; here's a reference [apple.com].
    • SETI (Score:5, Funny)

      by elliotj (519297) <slashdotNO@SPAMelliotjohnson.com> on Friday July 04, 2003 @06:35PM (#6369515) Homepage
      Personally though, I want to see how well it runs Seti@Home

      My bet is you still won't find any signs of Alien life. So it won't be any better than my old crappy ass P1 166.

      But good luck to ya.
    • by Andy_R (114137)
      But why on earth would you want to? Unless you are an intel/amd fanatic trying to prove a rather dubious point by crippling the Mac or an imb/apple devotee trying to skew the field by giving 1 cpu the entire 1Ghz bus bandwidth. Either way it's not going to give a useful result.

      If you can think of a good reason to turn off 50% of your processing, why not save a lot of money and go for one of the two mid-range single cpu G5 configurations that Apple will happily sell you?

      By testing in this ludicrous 'half a
      • I believe this is useful to allow developers to better understand their applications performance on a single cpu system, without the need to buy yet another mac. I believe that's why the tool is offered from the Developers portion of the site.

        I also remember a few games having issues on dual processor computers, a while back. Though most of these issues have been resolved now, it'd be interesting to see if the problems cleared up if you disabled a cpu.

      • by Have Blue (616) on Saturday July 05, 2003 @12:42AM (#6370885) Homepage
        You can't "give 1 CPU the entire 1Ghz bus bandwidth". The two CPUs have independent 1Ghz connections to the system controller. They only share the 400Mhz RAM bus and the rest of the system devices.
    • Bebox (Score:3, Funny)

      by fredistheking (464407)
      Does anyone remember the dual-ppc that the BeOS people were originally selling? Anyway, you could turn off one of the processors but if you wanted to, you could turn them both off. I think they evenrtually removed this feature. =)

      -
  • by Dak RIT (556128) on Friday July 04, 2003 @05:31PM (#6369193) Homepage
    Though dual processor benchmarks are not presented in detail here, it is worth noting that the G5 system benchmarked at 498 MFLOPS and 0.125 MFLOPS/MHz for scalar Jet3D performance when two processors were used.

    By adding a second processor, the MFLOPS/Mhz output only dropped from 0.127 to 0.125 MFLOPS/Mhz. This chip can definitely perform in a multi-processor environment. The P4 scored 0.096 MFLOPS/MHz with a single processor.

    Apple's benchmarks [apple.com] which were highly criticized by some, gave the Dual 2GHz Power Mac G5 a 194.5% performance advantage over a 3GHz P4 in SPECfp_rate_base2000. The G5 getting a score of 15.7, and the P4 getting an 8.07.

    NASA's study found the Dual 2GHz Power Mac G5 to score 498 MFLOPS for their Jet3D performance. A P4 running at 2.66GHz scored 255 MFLOPS: a 195.3% performance advantage for the G5 in this test. If we assume a direct correlation between MHz and MFLOPS for the P4 (which would actually overstate the performance of the P4) and increase the P4's score by 12.782% this would give the 3GHz P4 a score of 287.594 MFLOPS. This is still a 173.16% performance advantage for the G5, and NASA states that a 20% increase in performance for the G5 would be reasonable "when G5-aware compiler tools become available."

    So it would seem NASA's benchmarks go a long way in validating the benchmarks for the G5 that Apple released last month at the WWDC. In fact, NASA appears to be giving the G5 even better scores than Apple and Veritest did.

    The vector tests that NASA performed to test the G5's AltiVec instruction set produce some even more impressive results, and would be a good indication for why the G5 outpaced the Xeon and P4 by such dramatic amounts on real world tests (at times more than 700% faster than a 3GHz P4). "The vector version of Jet3D runs an order of magnitude faster than the scalar version (speedups of 10X-13X are typical)." The dual 2GHz G5 was benchmarked at 5177 MFLOPS (a 1040% increase over the scalar test) and 1.29 MFLOPS/MHz. This also seems accurate considering Ars Technica's claim that the AltiVec engine wasn't as well integrated into the G5 as it was in the G4. The 2GHz G5 (single cpu) scored 2755 MFLOPS, or 1.378 MFLOPS/MHz, which shows a slightly larger performance hit for vector operations than floating point operations when moving to a dual G5.

    Dak

    • by Anonymous Coward on Friday July 04, 2003 @05:37PM (#6369218)
      "NASA's study found the Dual 2GHz Power Mac G5 to score 498 MFLOPS for their Jet3D performance. A P4 running at 2.66GHz scored 255 MFLOPS: a 195.3% performance advantage for the G5 in this test."

      First, 498 vs 255 is 95.3% (instead of 195.3%) advantage.

      Second, why compare dual fastest G5 vs single mid-range P4? Singe 2GHz G5 scored 254 MFLOPS, it quite fast, but then again equally fast 2.66GHz P4 is available at $188.

      It would be much more interesting to compare dual 2GHz G5 against dual Opterons and Xeons.
      • by andreMA (643885) on Friday July 04, 2003 @06:50PM (#6369577)
        The 498 figure was presented strictly as an aside:
        Though dual processor benchmarks are not presented in detail here, it is worth noting that the G5 system benchmarked at 498 MFLOPS...

        More relevant, perhaps, are the figures in the raw MFLOPS graph:

        254: PowerMac G5, 2x2GHz, (single CPU only)

        255: Pentium 4, 1x2.66 GHz
        Alas, difficulties in cross-platform benchmarking rear their ugly head:
        Scalar Code:

        G4 using Absoft F90 v8: f90 -s -O -lU77 -N11

        P4 using Portland Group F90 v4.0-3: pgf90 -byteswapio -tp p7 -O1
        The author did apparently make an effort to use the compiler and flags best suited for each architecture if I read this correctly....

        Note that the higher level of optimization (-O2) and SSE/SSE2 options in the Portland compiler degraded Jet3D performance on the P4 system, and were therefore not used.

        I don't know how much I trust NASA tho. Afterall, they only do RealMedia and WindowsMedia streaming media. Perhaps there's some bias there in favor of Windows (yes, I realize that the testbed P4 system ran Red Hat. Lighten up)

      • by nsrbrake (233425) on Friday July 04, 2003 @07:41PM (#6369838) Homepage
        Go back and read the article. You have no idea what you are saying.

        1) One of the Mac's processors was disabled
        2) 195.3% advantage was on an MFLOP/MHz basis

        That is how they are comparing the architechture of the chip and it's performance outside of a MHz pissing race. They are in the same ballpark now MHz wise so why shouldn't they take a look at how the actual chip performs. Not to mention how much more will likely come out of the chip with maturing compilers to take advantage of the arch.

        • by Mr. Hankey (95668) on Friday July 04, 2003 @07:51PM (#6369872) Homepage
          It would be interesting to see how it compared to an Athlon at MFLOP/MHz, which has a higher performance to clock cycle rate (and much better floating point) than the P4. I wouldn't be surprised if the Athlon outperforms the G5 at similar clock rates. The P4 is specifically designed to achieve higher clock rates at the expense of instructions per clock cycle.

          Obviously a comparison against the Opteron or Itanium is not fair at this time, as they're not intended for the desktop but rather workstation audience. When the Athlon 64 comes out though, benchmarks of those vs. the G5 would be of interest as well.
      • Actually, both 195.3% and 95.3% are correct, depending on how it is phrased:

        1.) it is 95.3% greater than...
        2.) it is 195.3% of... ...or something like that.
    • by baseinfinity (18023) * on Friday July 04, 2003 @06:07PM (#6369376)
      Either way they're still benchmarking Apple hardware to be released in September versus Intel hardware that was available months ago. A quick look at Tejas and Athlon 64 specs will prove that both Intel and AMD have some whoopass coming down the line in Q4. At least this means Apple will be competitive still when the storm hits... but I don't think this hardware is revolutionary when compared to it's future peers.
    • Damn Dude, RTFA (Score:4, Interesting)

      by Mindcry (596198) on Friday July 04, 2003 @06:44PM (#6369549)
      The 498 MFLOPS figure was WITH 2 G5s!!!!
      With a single G5, the 2ghz got a 254, and the 2.66ghz P4 got 255 MFLOPs...
      Please read the article more clearly, this DOES NOT IN ANY WAY validate apple's earlier claims... here's the quote that was misread

      "Though dual processor benchmarks are not presented in detail here, it is worth noting that the G5 system benchmarked at 498 MFLOPS and 0.125 MFLOPS/MHz for scalar Jet3D performance when two processors were used."

      Followed by a chart showing the P4 2.66ghz with 255MFLOPS at the top and a G5 2ghz with 254MFLOPS at the bottom...

      So you could guess that a dual 2.66ghz would get about 499-500MFLOPS which would be a 0% performance advantage to the G5, and the P4 3.2ghz would be even faster...

      • by Dak RIT (556128) on Friday July 04, 2003 @07:06PM (#6369650) Homepage
        If you follow that little link I gave you for Apple's benchmark claims, you'll see that the performance advantage Apple is claiming for its Dual 2Ghz G5 (I wrote Dual if you reread) is almost identical to what NASA is claiming for the Dual 2GHz G5 against a 2.66MHz P4.

        Apple claims 15.7 for the Dual 2GHz G5, and the 3GHz P4 getting an 8.07. NASA gives the Dual 2GHz G5 498MFLOPS and the 2.66GHz P4 255MFLOPS.

        If you use your math skills: 15.7 / 8.07 about equals 498 / 255. So therefore we can draw the conclusion that they have similar results.

        Now, NASA only used a 2.66MHz P4 while Apple used a 3GHz P4. Although remember NASA's figure that the P4 had 0.096 MFLOPS/MHz? Give the P4 333 more MHz, and you find it has about 286.968 MFLOPS. NASA also suggests a 20% performance increase can be expected with compilers that take advantage of the G5.

        Although, even without this increase Apple's benchmark and NASA's benchmarks are very close. Which would lead one to draw the conclusion that Apple's benchmarks were in fact valid.

        I should also note that a P4 would not perform as well in a dual system as the G5 does. So your 500 MFLOPS number is a little rediculous. The G5 which is an amazing dual proc chip saw it's 254 MFLOPS for a single processor (508 when doubled) drop to 498 MFLOPS in a dual system. And the P4 isn't designed for a dual system, doesn't support HyperTransport, etc.

        Dak

      • Re:Damn Dude, RTFA (Score:5, Insightful)

        by dhogaza (64507) on Friday July 04, 2003 @07:07PM (#6369660) Homepage
        Except that

        1. They weren't using a compiler optimized for the G5, and expect performance to increase when they have that opportunity.

        2. Dual G5s appear to scale better than dual P4s. They're getting close to 2x performance with the dual G5s, much better than most folks are used to with SMP systems.
  • Summary (Score:3, Insightful)

    by LordOfYourPants (145342) on Friday July 04, 2003 @05:33PM (#6369204)
    I love the wording:

    "Benchmarks from the scalar version of Jet3D are shown in Figure 1 (MFLOPS) and Figure 2 (MFLOPS normalized by MHz). In terms of raw MFLOPS, the 2GHz G5 is about 32% faster than the 2GHz P4, 97% faster than the 1.25GHz G4, 142% faster than the 1GHz G4, and within 1 MFLOP of the 2.66GHz P4."

    Translation: Slower than the P4 for anyone who didn't look at the grid. And M stands for million. Not one.
    • Re:Summary (Score:3, Informative)

      by Anonymous Coward
      Translation: Slower than the P4 for anyone who didn't look at the grid.

      Real Translation: 0.4% slower, at 75% of the clock speed.
  • Curious... (Score:3, Funny)

    by Realistic_Dragon (655151) on Friday July 04, 2003 @05:35PM (#6369210) Homepage
    I wonder why none of the NASA boxes were running Windows? I mean, if it's an all sinigng all dancing solution to everything...

    (It's ok, you can mod me -1 Troll now. I'm just bitter about an edict on a project I'm working on.)
  • by jbridges (70118) on Friday July 04, 2003 @05:36PM (#6369215)
    What the heck is that a benchmark of? Divide by the Mhz to create a higher number on their nice little graph for the G5?

    Why a Pentium 4 2.66mhz?

    Why no Athlon?

    Why no Opteron?

    Why an old old version of RedHat 7.1?

    and so on....

    • Why a P4 2.66? That's probably what they had that was closest in clockspeed to 2ghz, maybe while still using the newest core. Plus this is still pretty close to 3ghz, so you know the P4 scores wouldn't double if you used one or anything.

      Why no Athlon? They probably didn't have one and with the P4 at 3ghz and climbing, the old althon is becomming less and less significant for these pure number crunching apps. Plus maybe they've done previous tests that said that P4 they uesd was faster than an equivelent a

      • They couldn't get a hold of a super-cheap Athlon XP or even a sub $1500 Opteron server, but they got a hold of an Apple G5 which isn't even available for sale???

        Puh-lease... The gripe with the SPEC benchmarks was that Apples numbers for the competition were WAY below the OFFICIAL numbers, ot that Apples numbers for their own equipment was crap.

        Jeeze...let's at least wait till these things are SHIPPING.
    • Why No Cray? (Score:5, Insightful)

      by Detritus (11846) on Friday July 04, 2003 @05:55PM (#6369309) Homepage
      Maybe because that was the hardware and software available to the testers. Contrary to popular belief, government employees do not have unlimited budgets to buy stuff. The last time I worked in a government office, some of the furniture was older than I was and my PC was built from scrounged parts.
    • by Jeffrey Baker (6191) on Friday July 04, 2003 @06:15PM (#6369411)
      I think it's pretty obvious why they tested the G5: their Altivec program is 13X faster than their scalar program. They don't mention the SSE2 so I assume they have an investment in Altivec programs. Therefore they would naturally be interested in comparing the G5 versus the XServe and G4. Until Intel releases the 34.5GHz P4 (13X 2.66GHz), there doesn't seem to be any reason to run out and buy a latest P4 just for this comparison.

      And surely the version of RH Linux hardly matters. Maybe they benchmarked using this OS because (shock, horror) it is what they use daily.
    • The unit MFLOPS/MHz is a little weird. Let's simplify.

      / MFLOP \
      | ----- |
      \ S /
      -----------
      / MCYCLE \
      | ------ |
      \ S /

      Multiply by the reciprocal...

      MFLOP S
      ----- * ------
      S MCYCLE

      Millions cancel, seconds cancel...

      FLOP
      -----
      CYCLE

      So it seems that this unit is equal to 1 floating point operation per CPU cycle. That makes a little bit more sense as a unit.
  • Portland compiler (Score:3, Interesting)

    by PineGreen (446635) on Friday July 04, 2003 @05:38PM (#6369229) Homepage
    I have very bad experience with Portland compiler; I wonder what the results would have been if they had used Intel Fortran Compiler....
  • fortran compiler (Score:5, Informative)

    by mz001b (122709) on Friday July 04, 2003 @05:38PM (#6369230)
    It is interesting to note that they used the Portland group compiler instead of the intel compiler. For the CFD code that I work on (which is mostly Fortran), the Intel compiler produces much faster code than the Portland group compiler (as much as 50%).
    • by wagnerer (53943) on Friday July 04, 2003 @07:53PM (#6369878)
      You'll want to be careful with the code the intel compiler spits out. It may be fast but some scientific codes compiled with it give incorrect answers. Compile the same code on any other f90 compiler and it gives the correct answer. Not something to inspire confience in your answers.
  • by binaryDigit (557647) on Friday July 04, 2003 @05:39PM (#6369235)
    If there budget is such that dualie 2Ghz G5's are a possibility, then it's somewhat surprising that they A) used such low powered P4's B) that they didn't include Itanic2 systems. Seems that their report really just pointed out stuff that we already knew, the PPC is typcially faster per mhz than the P4 (hell, just about anything is better per mhz than the P4). Interesting to note that on the vector test, the G5 outperformed the G4 is a fashion that is almost purely based on the increase in Mhz (i.e. other system improvements didn't really seem to help much). Compiler perhaps, though some of the architectural improvements would seem to be not dependant on that?
  • by reporter (666905) on Friday July 04, 2003 @05:40PM (#6369236) Homepage
    The G5 by Apple is really a workstation but has been mis-labeled a "PC". The floating-point performance of the G5 crushes any workstation by Sun. In fact, the heart of the G5 is a Power4 server-based microprocessor. At "SPEC [spec.org]", you can easily find the performance of a Power4 @ 1.45 GHz. Its SPEC2000 rating for floating point is 1097. When you scale that to the 2.0 GHz processor in the G5, you conclude that it has a SPEC score of about 1500.

    Apple has just created a new market for itself among the hardcore engineers who use workstations for numerical simulations like HSPICE, etc. Steve Jobs lucked out -- again.

    By the way, the bell tolls. It tolls ominously for Sun Microsystems.

    • by Phroggy (441) * <slashdot3@@@phroggy...com> on Friday July 04, 2003 @06:03PM (#6369350) Homepage
      Steve Jobs lucked out -- again.

      Um, yeah, sure is lucky Apple found the G5. I'm sure they had nothing to do with its development. It's not like Apple has been involved with development of the whole PowerPC architecture since the early 90s.
    • The Power4 has 128MB of L3 cache, to get comparable performance to a Power4 the G5 needs considerably higher clock speeds. Also Sun hasn't been competitive in the single and dual CPU workstation market for some time. The only things they had going for them were large memory support and large CPU scalability, now everyone is getting large memory support with the transition to 64bit so they only have large cpu counts to fall back on.
    • What is the difference between a PC and a workstation? I think its pretty clear the term workstation as a distinguishing label died long ago, some time after "PC" performance on the desktop destroyed "workstation" performance.
    • At "SPEC", you can easily find the performance of a Power4 @ 1.45 GHz. Its SPEC2000 rating for floating point is 1097. When you scale that to the 2.0 GHz processor in the G5, you conclude that it has a SPEC score of about 1500.

      Wrong Conclusion!

      According to this pdf (page 13) [ibm.com] G5 @ 1.8GHz has 1051 SpecFP.
      At the same time Power4 @ 1.7GHz has 1598 SpecFP !!! [spec.org]

      It is very clear that Power 970 (G5) is much-much slower in floating point than it's Power4.

  • by FooGoo (98336) on Friday July 04, 2003 @05:43PM (#6369250)
    The only benchmarks that matter is my impression of the system while using the apps I use. Everything else is opinion.
  • Costs (Score:3, Insightful)

    by mgkimsal2 (200677) on Friday July 04, 2003 @05:44PM (#6369255) Homepage
    Something which seems to get lost in the Mac/PC debates *sometimes* is the cost factor. I looked those graphs and thought "Wow - mac is faster at this benchmark". Then I looked up pricing - minimum I can get that mac for would be $1999. An equivalent PC system with the P4 2.66ghz is probably under $900 (didn't spec it out entirely, just did a rough lookup on Dell). Great - Mac is faster. But I can apparently get within reasonable range on PC hardware for probably 50% less cost.

    I'd read some thread a while back on another board saying that "Macs are cheaper than PCs". I still can't believe anyone would make that argument. Doesn't being really good in a few areas satisfy the mac people? Do they have to try to spin higher costs as 'lower' (craziest thing I'd ever heard...)
    • by mgkimsal2 (200677) on Friday July 04, 2003 @05:47PM (#6369277) Homepage
      $2999 for the mac 2x2ghz
    • Re:Costs (Score:5, Insightful)

      by nordicfrost (118437) * on Friday July 04, 2003 @06:01PM (#6369342)
      Mac is cheaper than PCs, even in laptops. It all depends on what you'll use it for. I'm trying to convince a pal that the iBook would be a better purchase for his mother than a Fujitsu Siemens PC. The iBook is rougly 9500 NOK and the Siemens 11500 NOK.

      The difference in speed mHz, RAM etc. is irrelevant for a person just getting used to computers and the net. When she is having weekly problems with the Siemens / Windows machine, it will be lost money in time. While the Mac is cheaper in usage, because of less "frustration time" and less hassle.

      This is an argument I would strongly disagree with, if you asked me two years ago. But since then, I have come to the conclusion that the Mac simply work better for the lay people. It does the work, and faster because there are less frustrations and less hassle.
    • Re:Costs (Score:5, Interesting)

      by MalleusEBHC (597600) on Friday July 04, 2003 @06:20PM (#6369431)
      I'd read some thread a while back on another board saying that "Macs are cheaper than PCs". I still can't believe anyone would make that argument.

      I'll make that argument any day of the week if you want to consider TCO. My family got a Powermac G4 in 1999, and it is still the daily use computer for them. (I have my own Cube, which is basically the same for performance comparisons.) That thing still does everything that they can ask of it and then some. Hell, it can still play all the games that I want to play, save UT2k3. The great part is that it is still humming along perfectly, and I don't see any reason why it won't last two or three more years. Find me a PC that you will still be using daily 6 or 7 years later.

      This doesn't even take into account all the time and headaches that have been saved from using a Mac. Taking out the "Did you accidentally kick the power cord out?" type phone calls I've gotten to help them, I can think of maybe twice that they have had to call me and troubleshoot. There is no pricetag on this peace of mind.
  • The G5 (Score:3, Insightful)

    by Eric(b0mb)Dennis (629047) * on Friday July 04, 2003 @05:44PM (#6369259)
    The G5 really is a powerful machine, and i wouldn't mind owning one... if only the price for maintaining a mac wasn't so high...

    Their scheme for OS X is the equivalent of Microsoft charging $100+ for a service pack, I just don't understand it.

    I've used OS X, and it blows everything else out of the water in elequency and it seems the perfect balance between productive and 'cool factor'

    But until I win the lottery, I'll stick with my cheap x86 machines
    • Re:The G5 (Score:5, Insightful)

      by Dak RIT (556128) on Friday July 04, 2003 @05:53PM (#6369300) Homepage
      Microsoft Windows XP Pro: Full price: $299
      Microsoft Windows XP Pro Upgrapde: $199
      http://shop.microsoft.com/Referral/Productinfo.asp ?siteID=10798

      MacOS X 10.3/2/1 Full price: $129
      http://www.apple.com/macosx/

      Microsoft Windows XP Pro (5 Users): $1315.60
      MacOS X 10.3/2/1 (5 Users): $199

      If you bought Windows XP ($299), and then can upgrapde to Longhorn for $199, you paid $498. If you bought MacOS X 10.1, 10.2, 10.3, and 10.4, you paid $516. Pretty similar, and that's assuming you only have to pay $199 for Longhorn. In the meantime, Apple users enjoy continued advance, while Windows stagnates for 4+ years.

      Do the same with a family licence of 5. Buy Windows XP for $1315.60, then upgrade for $875.60: $2191.20 (over 4 years, for 5 people: $109.56/user/year).

      Buy MacOS 10.1, 10.2, 10.3, 10.4 (5 User Licence): $796 (over 4 years, for 5 people: $39.80/user/year).

      Using http://shopper.cnet.com I found a copy of Windows XP Pro for $207, and an upgrade for Windows XP Pro for $177. I found a copy of MacOS X 10.2 for $98.

      If these prices hold over to the newer Operating Systems these companies release, then Windows would cost $384 (23% savings), and MacOS X would cost $196 (24% savings). If you bought every point upgrade Apple released it would cost $392.

      Dak

    • Wrong. (Score:4, Insightful)

      by Tokerat (150341) on Friday July 04, 2003 @05:54PM (#6369302) Journal

      Their scheme for OS X is the equivalent of Microsoft charging $100+ for a service pack, I just don't understand it.
      Apple regularly issues Security Updates, Bug Fixes, and Mac OS X Updatres through the Software Update system. This, the equivilant of a Service Pack, is free.

      The major OS version updates are when new features are added, etc. That is the equivelant of upgrading 98 to XP. The cost of buying a Mac is high. The cost of maint. is probably less than a Windows box.
  • by Cordath (581672) on Friday July 04, 2003 @05:55PM (#6369308)
    It was interesting to see this paper devote so much effort to the completely useless metric of MFLOPS/MHz. This measurement has absolutely nothing to do with performance, but rather, with the approach taken by the chip manufacturer. You can do more in one clock cycle, as AMD historitcally has done, or less, but optimize for faster clock speeds, as Intel has in recent flavors of the Pentium.

    One might be tempted to design a chip that does more in one cycle and then clock it as fast as a chip that does less in one cycle. Unfortunately, while reality is a little more complex than this, the basic reason is that the more a chip does per cycle, the more heat it generates per cycle. If you try to squeeze too many cycles through it in a second it will fry.

    So showing that the G5 has better performance per clock cycles is no more useful than showing that an AMD chip has better performance per clock cycle than an Intel chip. All that matters is how much performance you can get from a chip before it cannot be clocked any faster without requiring unreasonable cooling methods.

    All this paper shows is that, while the G5 is designed to do more in a clock cycle than a P4 is, the chip tested is ultimately not any faster than the P4 they benchmarked it against. It remains to be seen how the G5 will do at higher clock speeds. With this in mind, it would be *far* more useful to see heat dissipation stats on the G5 since that might give us some idea how close to it's design limits. If it is cranking out high-end P4 performance and running cool *then* I will be impressed.
  • Interesting Thought (Score:5, Interesting)

    by ciroknight (601098) on Friday July 04, 2003 @05:57PM (#6369321)
    Apple has been making better software for years, everyone agrees; They just never had the hardware to back them up. Then every time they do crop up with better hardware, everyone criticizes them and says that it's just not possible, PC hardware is always better they say. But now they've proven you wrong... TWICE, and some trolls STILL don't believe them. It's a sad world. I just wish Apple would open up at least their motherboards a little more, make Macs more customizable, more like PC's so they can start dominating again.

    There's also one benchmark I'de love to see. Power Mac G5 vs Sun UltraSPARC III. It's fair: they're both 64-bit procs, and it would really make people look at it in businesses that only look at supercomputers as viable. Then maybe people would start giving Apple and IBM some credit.

    My 2 cents (Canadian). Thanks.
  • MFLOPS per $ (Score:5, Interesting)

    by mgkimsal2 (200677) on Friday July 04, 2003 @06:02PM (#6369348) Homepage
    Why not show an mflops/$ chart? Related to my 'cost' post as well, but I felt it deserved its own post. :)

    This seems to confirm my belief that most mac people don't buy their own hardware, but get it through work or school.
  • Vector Performance (Score:5, Insightful)

    by Japer Lamar Crabb (670674) on Friday July 04, 2003 @06:08PM (#6369381)
    >>Vector performance of the G5 remains excellent, and is inline with current G4 systems on a per clock cycle >>basis. As a result, raw vector performance of the G5 will be boosted simply by its higher clock speeds relative >>to current G4 systems.

    This would seem to be one of the more interesting points made, actually. Prior to the announcement of the G5s, speculation on the PPC 970 suggested that it would be stellar with FP & so-so with integer; the real question surrounded how well IBM would implement SIMD. Many were pessimistic. Given that it seems like they've managed to add it efficiently a scaled-down POWER4 core, future refinements could make this series of chips (PPC 9X0s) real monsters.

    But the future viability of that roadmap (given how ruthless the company as a whole tends to be when faced with departmental money losses) depends as much upon the success of IBM's Linux strategy as it does on its success in the PowerMac line.

    [With apologies to BadAndy of the Ars Technica boards; thanks for sharing your insights.]
  • In all fairness... (Score:5, Insightful)

    by Znonymous Coward (615009) on Friday July 04, 2003 @06:09PM (#6369382) Journal
    It's not Apple's G5, it's IBM's 970 and it's the shizzle.

    • From Crazy Apple Rumors: [crazyapplerumors.com]

      Apple Rocked By "G5" Scandal.

      Just one week after the "G5"'s introduction, Apple has been hit by shocking allegations that the name of the chip powering the computer is nothing more than a tawdry attempt at huckstering, worthy of the lowest flim-flam artist.

      According to highly placed industry sources, the "G5" is actually the IBM PowerPC 970, and Apple has been using the "G5" name simply to sell more computers.

      Through a systematic application of underhanded techniques known as "m

  • by Anonymous Coward on Friday July 04, 2003 @06:14PM (#6369407)
    It was a hardware simulator running on a soundstage.
  • OS X 10.2.7 (Score:5, Interesting)

    by Greedo (304385) on Friday July 04, 2003 @06:15PM (#6369412) Homepage Journal
    I was RTFA, and this caught my eye:

    Additional Notes: The G5 system was running Mac OS X 10.2.7 and ...

    I'm only running 10.2.6, and Software Update says nothing new is available. What's up with that?

  • by vitaboy (610992) on Friday July 04, 2003 @06:22PM (#6369443)
    This is the killer statement in the whole article:

    "The vector version of Jet3D runs an order of magnitude faster than the scalar version (speedups of 10X-13X are typical)." The dual 2GHz G5 was benchmarked at 5177 MFLOPS (a 1040% increase over the scalar test) and 1.29 MFLOPS/MHz."

    5177 MFLOPS when running a Velocity Engine optimized version of Jet3D.

    Now, how much does an P4 extrapolated to 3.2 GHz get? Like 288 MFLOPS?

    Someone please explain to me how 5177 MFLOPS and ~300 MFLOPS are even comparable.

    As the Mathematica guy said, the competition is no longer high-end PCs, it's now $10,000 UNIX workstations...and the G5 is still faster than any of them.

    No wonder the G5s smoke the dual Xeon in the Photoshop, Mathematica, Logic, and Luxology app bake-off. All these apps would have been optimized to use the Velocity Engine.

    If I were a scientist doing lots of image processing and vector calculations, I'd need a cluster of about 18 or so 3.2 GHz P4 machines to keep up with the dual 2 GHz G5 PowerMac running a typical Velocity Engine optimized app.

    That's a sweet 5177 MFLOPS for you - evidence the G5s rock as hard as Apple has been indicating.

    • by WasterDave (20047) <davep&zedkep,com> on Friday July 04, 2003 @06:59PM (#6369615)
      Someone please explain to me how 5177 MFLOPS and ~300 MFLOPS are even comparable.

      They're not, which is what makes this whole benchmark so entirely useless.

      Look at it: The conclusion, basically, is that there's no point in running CFD code using scalar FP. So why didn't they port their code to SSE2? P4's, and particularly the new 800MHz FSB P4 get data through SSE2 code like there's no tomorrow.

      Nah, I'll listen when someone compares SSE2 and AltiVec properly. Until then it's just more blah. Don't get me wrong, I'm rapidly turning into the biggest Mac fanboy you've ever seen (Cocoa, since you ask) but the G5's are not the quantum leap Apple are making them out to be. Back in contention? Sure, but I promise you a dual Opteron 2GHz will blow the doors off a dual G5.

      Dave
      • by Anonymous Coward on Friday July 04, 2003 @07:30PM (#6369794)
        I recently got the chance to do a testrun, doing some airflow simulation on a G5 1.8GHz demo machine, and with altivec optimizations it clocked in at roughly 2100MFLOPS average for 5 runs(I could probably get better results with a better compiler though), while the dual Opteron 1.8(which the place where I did the testrun has bought 10 boxes of for their renderfarm), running Suse Linux, and my program re-compiled for x86-64 and SSE2 performed at about 2960MFLOPS average, but that could probably be improved with a better compiler too, but I had to use GCC at this time. Both machines had 4GB RAM btw.
  • by jbridges (70118) on Friday July 04, 2003 @06:49PM (#6369571)
    Found this from last Jan:

    Date: Mon, 13 Jan 2003 23:29:38 -0500
    From: Craig Hunter
    Subject: G4 vs. P4 performance

    I have been following the discussion of Rob Galbraith's benchmarks with much interest, as I have spent a good deal of time testing, optimizing, and benchmarking software for the G4 (OS X) and P4 (Linux).

    The first thing to realize is that there are numerous benchmarks that show the P4 is faster, and there are numerous benchmarks that show the G4 is faster. What matters? Well, probably the benchmarks that apply to the kind of work you do. For people doing photo processing with the software Rob tested, his results are extremely relevant. But, someone working with a program optimized for AltiVec and dual processors might have a completely opposite experience.

    Just to give an example of a benchmark that goes the other way, see this chart.

    (You're welcome to mirror this benchmark image, since my web site may not handle a lot of traffic). These real-world results come from the Jet3D computational fluid dynamics noise prediction software, which I developed for my doctoral thesis and currently use in my work at NASA. Jet3D is written in a combination of FORTRAN 77, FORTRAN 90, and C, and is optimized for AltiVec and dual processors on G4 hardware. When compiled on Linux using Intel's ifc compiler tools, Jet3D also becomes optimized for the P4 (using the various SIMD extensions available on the P4).

    As you can see, the G4 does quite well here. A dual processor 1.25GHz G4 system is more than 3.5X faster than a single processor 2GHz P4 system. Though it's not shown on the chart, a single 1.25GHz G4 processor benchmarks at about 1589 MFLOPS, 1.9X faster than the P4. If you look at MFLOPS per MHz for a single processor, the G4 comes in at 1.27 MFLOPS/MHz, while the P4 comes in at 0.42 MFLOPS/MHz. If you want a good example of the MHz myth, look at the Cray, which comes in at 1.78 MFLOPS/MHz with only a 500MHz processor, beating both the G4 and P4.

    Without AltiVec, the Jet3D benchmark would be about 794 MFLOPS on the dual-1.25GHz G4, which erases the performance lead over the P4. And then, using only a single processor, the 1.25GHz G4 benchmarks at about 418 MFLOPS, which is about half as fast as the P4. And all of a sudden, the G4 doesn't look very compelling. For the Jet3D benchmark, AltiVec and dual processors are key (AltiVec more so than dual procs). This is true for most benchmarks I have looked at; thus numerically intensive applications that can't use AltiVec and/or dual processors are likely to suffer on the G4.

    In the case of Jet3D, it was easy to optimize for AltiVec. I was able to hand-vectorize about 10 lines of code within the guts of the FORTRAN algorithm and convert the computations to C for easy access to AltiVec hardware instructions. It had a huge effect for not a lot of work. For other more complicated cases, it may be possible to use the VAST compiler tools to automatically vectorize and tie in with AltiVec (VAST has parallel tools also). But in some cases, vectorization is not possible or feasible. In those instances, you're stuck with the processor's scalar performance, and the P4 generally has better scalar performance than the G4 in my experience. One final note: these are my personal views, and do not represent the views of NASA Langley Research Center, NASA, or the United States Government, nor do they constitute an endorsement by NASA Langley Research Center, NASA, or the United States Government

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