970 vs. 970fx

Discussion in 'Buying Tips, Advice and Discussion (archive)' started by alexf, Aug 21, 2004.

  1. alexf macrumors 6502a

    alexf

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    #1
    I am thinking of getting a G5 2.0GHz and am debating between a Rev. A and Rev. B (probably with the upgraded graphics card)... I want to pretend for a moment that money isn't a factor (although in reality it is) and compare the two.

    Would I notice any difference between the original 970 chip and the 970fx? It the 970fx really superior in many ways? Energy consumption is important to me, and I hear that the chip is improved in this area, but how big a difference would this really be? And how about performance improvement?

    Lastly, is the internal architecture any different on the two models? if I recall, the insides look slightly different in some ways, or...?

    I'll be grateful for any expert guidance. :)
     
  2. invaLPsion macrumors 65816

    invaLPsion

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    #2
    You will not notice a shred of difference between the two chips. The 970FX has double the data cache, however, the difference in performance is absolutely unnoticeable. The chip supposedly runs quieter and with less power consumption, but reports from users indicate that the difference is minimal.

    In terms of internal architecture, the new G5s are .25 inches wider.
     
  3. Sun Baked macrumors G5

    Sun Baked

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    #3
    Actually they are the same the dude that did the article ****ed up.

    [​IMG]
     
  4. alexf thread starter macrumors 6502a

    alexf

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    #4
    What exactly is .25 inches wider?

    Also, when you say the chip runs quieter, do you mean less fan noise? I didn't know that chips really made noise to begin with... (perhaps my ignorance)
     
  5. invaLPsion macrumors 65816

    invaLPsion

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    #5
    The case is wider by a quarter of an inch.

    The fans are what I meant as being quieter.
     
  6. alexf thread starter macrumors 6502a

    alexf

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    #6
    So the computer is actually physically larger? This is surprising...

    (As if it wasn't already big enough! Then again, .25 inches is almost nothing...)

    Are the fans really noticeably quieter? Has anyone done any comparisons?
     
  7. shadowband macrumors member

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    #7
    Don't assume that the rev b 1.8/2.0 powermacs have the 970fx chip. I just took delivery of a BTO 2.0GHz powermac last month and it has the 970. The 970fx will most likely be phased into the 1.8/2.0 line at some point, but there's no confirmation that this has happened as of yet.

    To determine which chip is used, refer to the procedure following thread:
    http://forums.macrumors.com/showthread.php?t=84191
     
  8. QCassidy352 macrumors G3

    QCassidy352

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    #8
    according to that graphic, the newer chip consumes MUCH less power... am I missing something?
     
  9. alexf thread starter macrumors 6502a

    alexf

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    #9
    Right, but I recall reading a couple of recent posts that stated that all of them are indeed now shipping with the new chip.

    In any case, as the previous poster stated, it probably wouldn't matter at all to me as the end user what chip is inside performance-wise, but as far as noise and energy are concerned, the new chip might be nicer.
     
  10. Sun Baked macrumors G5

    Sun Baked

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    #10
    Yes, look at the highlighted text in the quote -- the new 970FX CPUs do not have a larger L1 inst cache, which is what the author of the original article was saying.
     
  11. alexf thread starter macrumors 6502a

    alexf

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    #11
    Yes, actually it's about 50%! If this is true, that is quite a bit. :eek:
     
  12. Sun Baked macrumors G5

    Sun Baked

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    #12
    Hmm...

    Lowendmac (along with many other sites) has the SP1.6PM as

    size (HxWxD): 20.1" x 8.1" x 18.7" (51.1 x 20.6 x 47.5 cm)

    And apple has the new DP2.5PM as

    # Height: 20.1 inches (51.1 cm)
    # Width: 8.1 inches (20.6 cm)
    # Depth: 18.7 inches (47.5 cm)

    ---
    I can't seem to find the .25 missing inches. :(
     
  13. ifjake macrumors 6502a

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    #13
    i was under the impression that less power consumption meant less heat generated, but it seems that that's not correct as that graphic states that the junction temp. range, whatever that means, is larger for the 970fx. anyone know what's up?
     
  14. Sun Baked macrumors G5

    Sun Baked

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    #14
    Motorola did the same thing for the "performance spec" processors that Apple was consuming.

    The physically hotter temp should allow IBM/Apple to turn the clock up a bit.

    It wouldn't be too surprising to see the 2.5GHz CPU being classified as a 105°C chip.

    ---

    Of course under Motorola, their market was the 85°C range for the embedded market and the chips Apple used weren't really part of their public spec.

    One of the reason the chips on their website always took so long to catch up in speed to the PowerMacs -- because the PowerMacs were able to use a hotter chip and the rest of Motorola's market didn't.
     
  15. QCassidy352 macrumors G3

    QCassidy352

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    #15
    yeah, I got that part of it... but some ppl were saying that there was no practical difference between the two chips. Seems to me that 1/2 the power consumption would be a practical difference.
     
  16. vga4life macrumors 6502

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    #16
    It's not true.

    Nobody has yet managed to make a 90 nm chip show any significant power savings compared to 130nm. All the industry estimates of power savings based on the savings seen in previous die shrinks turned out to be wrong.
    (Compounding the problem, the 90nm chips are physically smaller. Result: more heat in a smaller area requiring extreme cooling measures.)

    Intel's 90nm Prescott P4's actually consume much more power than the previous 130nm Northwood core. IBM made big claims of 90nm power savings before they actually started making 90nm chips. Now you can dig all day but you will never find real power consumption numbers for the 970fx. They're simply unpublished and unavailable unless you sign NDAs (or get ahold of a 970fx and run your own analysis). That graphic is long, long, out of date.

    -vga4life
     
  17. alexf thread starter macrumors 6502a

    alexf

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    #17
    Confused

    So if this is all true, what is all the hype about the 970fx all about?

    I am confused: I thought the 970fx was supposed to run cooler, and therefore could be fit into a smaller computer (like the iMac), as well as run more silently due to less fan noise. What's up?
     
  18. vga4life macrumors 6502

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    #18
    It *WAS* supposed to be cooler, etc. It's not.

    The only upside to a 90nm chip right now is for the manufacturer: more chips fit on a single wafer of silicon, increasing fab capacity. For everyone else (computer manufacturers who bhave to design fancy cooling systems for these chips and consumers who have to live with hotter, noisier computers), 90nm chips just plain suck.

    In the case of the 970fx, IBM is seeing such poor yields that this capacity increase hasn't materialized - 970fx yields are ultra-low, and this is why the G5 imac is nowhere to be found. Not enough CPUs.

    Basically the 970fx is a motorola-grade fiasco.

    -vga4life
     
  19. alexf thread starter macrumors 6502a

    alexf

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    #19
    If I may ask, where did you get this information?

    Also, the new iMacs are due to be released in a matter of days. From my understanding the 970fx was an important part of the reason the G5 iMac is possible.
     
  20. vga4life macrumors 6502

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    #20
    IBM's 90nm yield problems are well known (especially in the 300mm wafer facility):
    http://reviews.infoworld.com/article/04/07/19/HNibmchipgroup_1.html?PROCESSORS

    Apple explicitly said in their conference call that chip availability was the reason the imac G5 was delayed until next month.

    The 970fx probably does use a little less power than the 970, but not 50% less. Also the heat is concentrated in a smaller area due to the smaller die size, meaning more efficient cooling is necessary (see the 2.5GHz PowerMac's setup)

    -vga4life
     
  21. alexf thread starter macrumors 6502a

    alexf

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    #21
    So essentially, does this mean that, say a G5 with a 970 chip may in fact be QUIETER than a newer one with the 970fx chip?

    Right, I understand the chip availability problem for the iMac, but what does this have to do with cooling problems?
     
  22. Catfish_Man macrumors 68030

    Catfish_Man

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    #22
    I'm sorry, but you're wrong. Typical power for a 2GHz 970fx is 24.5 watts (this is probably counting PowerTune, so the peak/typical ratio is going to be somewhat higher than for the 970). For a 2GHz 970 it's 66 watts. This has been confirmed from IBM in more than one place (see the G5 threads on macnn and arstechnica). Either they're blatantly lying, or you're wrong (or, option 3, you have access to non-public info about the fx and are violating your NDA).
     
  23. alexf thread starter macrumors 6502a

    alexf

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    #23
    Wow, this is getting interesting...

    I (a measely designer who knows virtually nothing about this and just wants to know which chip would be quieter and more power efficient), will sit back and enjoy watching you two duke it out (respectfully, of course). :)
     
  24. oingoboingo macrumors 6502a

    oingoboingo

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    #24
    The new iMacs are already months late. The PPC 970FX has supposedly been in products since January 2004 (when the XServe G5 was announced and shown at MWSF). The fact that it is now almost September and we are still waiting for the iMac G5, and supplies of high-end PowerMac G5s are still highly limited indicates that the 970FX is not being produced in large numbers yet. Apple said as much in their most recent financial results conference call where they blame IBM for the delay in shipping iMac G5s.
     
  25. Sun Baked macrumors G5

    Sun Baked

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    #25
    And IBM testing of a production PowerMac G5 2.0GHz PPC970 says it got 79W max power dissipation using RC5-72.

    While Freescale tested the same type of machine using Dhrystone (their benchmark for typical) at 91.1W

    So no telling what it really is, but since there is an enire module running it looks like the CPU+daughtercard Powersupply/circuits can be up there quite a bit.
     

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