Old 4 GHz i7 vs new 4 GHz i7

Discussion in 'iMac' started by Thermonuclear, Oct 16, 2015.

  1. Thermonuclear macrumors 6502

    May 23, 2009
    The old 4 GHz Core i7-4790: http://www.cpubenchmark.net/cpu.php?cpu=Intel+Core+i7-4790K+@+4.00GHz&id=2275

    The new 4 GHz Core i7-6700: http://www.cpubenchmark.net/cpu.php?cpu=Intel+Core+i7-6700K+@+4.00GHz&id=2565

    The deltas:

    Turbo boost: DOWN 4.55%
    Single thread performance: DOWN 9.69%
    Multithread performance: DOWN 3.36%
    Power efficiency: DOWN 7.95%

    Thanks a bunch, Apple.

    At least the memory can be still be upgraded by the user, although I'll bet that this feature will be gone in next year's model.
  2. Melodeath macrumors 6502a

    Dec 9, 2009
    And yet here, the opposite conclusion - https://www.pugetsystems.com/labs/articles/Haswell-vs-Skylake-S-i7-4790K-vs-i7-6700K-641/

  3. Jimmdean macrumors 6502

    Mar 21, 2007
    Probably too early to jump to real conclusions, although we've known for quite some time that the performance increase at the desktop level was going to be marginal. Normally you can mitigate some of that by factoring in the additional features that a new chipset offers, but Apple chose not to integrate a lot of those in this iteration...
  4. Thermonuclear thread starter macrumors 6502

    May 23, 2009
    The above tests have the old i7 stuck with 1600 DDR3 RAM while the new i7 is allowed 2133 MHz DDR4 RAM. In the real word, the new 4 GHz iMac is stuck with old and slower DDR3 RAM, so those tests have little meaning. Also, in the links I posted there were hundreds and thousands of samples, while the sample count from Puget Systems is just one.
  5. garyleecn macrumors 6502a

    Jul 25, 2014
    well, the real conclusion is there is little to no performance gains... probably runs a little cooler on the new version, but no noticeable performance difference?
  6. Jimmdean macrumors 6502

    Mar 21, 2007
    it's certainly no reason to upgrade from the last model...
  7. mashinhead macrumors 68030

    Oct 7, 2003

    I'm confused by the comments about the new iMac i7 being allowed ddr4 ram when it ships with ddr3
  8. majestice macrumors member

    Oct 16, 2015
    He is talking about the processor test computers when he mentions ddr4.. not the iMac
  9. majestice macrumors member

    Oct 16, 2015
    The RAM on old computer is CL11 and the new one is CL15.. so if you divide these by their MHz the older 1600MHz RAM actually comes out faster than 2133MHz on the new one
  10. fob macrumors member


    Sep 11, 2015
    In other words this update is a placeholder to sell something "new".
  11. Jimmdean macrumors 6502

    Mar 21, 2007
    You're not wrong, but blame Intel as much as Apple. The actual CPU improvements this generation were mostly made in the mobile sector. The desktop sector had some interesting chipset improvements, but not in these iMacs...
  12. majestice macrumors member

    Oct 16, 2015
    Well there is the support for 64gb of RAM instead of 32gb but in the end I can't find 16gb sticks in china and when they come here they'll be super expensive so I'm just gonna stay at 32. But I have to admit I am bit bugged about the fact that I have to buy new computer now to replace my 2011 iMac.. back in 2011 I got kinda stuck between standards. The USB3 refresh came in 2012 model. Now we were left out of TB3 and USB-C that should have been possible with skylake. Not having that DDR4 is not that big of a deal for me but the most likely on next refresh we see some I/O changes. Wishful thinking in me was hoping they put R9 Fury Nano to iMac at this refresh (even if underclocked) since it looks like there's quite a lot of empty space within the comp.. but that would have been too good. 2012 Apple also went nVidia and I was stuck with AMD and lack of CUDA support on many apps I used. Maybe next year Apple will jump there again when Pascal comes out which is supposed to be a huge jump in GPU with the shared memory between CPU and GPU. Anyways this new 5K imac is most likely going to be almost twice as fast as my old 2011 but I would have still wished Apple would have been bit more cutting edge with this release
  13. xmichaelp macrumors 68000


    Jul 10, 2012
    No, it's simply the best processor intel has available.
  14. Thermonuclear thread starter macrumors 6502

    May 23, 2009
    Essentially true. Perhaps if Intel had offered a better chip, then Apple would have used it instead. And in a sense, the i7-6700 is a better chip if only its integrated graphics capability were used. Inside an iMac, the i7-6700 integrated graphics is like an albatross which drags down the CPU's specified capabilities even when it's not being used. The unused graphics adds to the per chip cost as well by about 10% compared to the i7-4790 as indicated by end user retail pricing from Intel.

    The space taken by the integrated graphics silicon, about 40% of the total, could have instead be used for much more L3 cache or maybe extra cores. Given the relatively slow notebook memory used in the iMac, I'd prefer the extra cache; if faster desktop memory DIMMs were used, then perhaps an extra pair of cores would be a better choice. Either way, once again we see the sort of design compromises incurred when a desktop computer is built from notebook parts.

    And so the fact remains that customers would have been better served if Apple had resisted marketing spin temptation and had just used the old i7-4790.
  15. Juliovalverde macrumors newbie

    Oct 5, 2015
    However, talking about real performance INSIDE the iMac, eventhought we have to wait some benchmark...

    We could say that the new iMac has improved. Taking into account the new CPU which is until 7 Celsius cooler.

    Therefore I dear to say there is a jump while intensive tasks. Remember the heat of the old one with m295x and i7
  16. Malus120 macrumors 6502

    Jun 28, 2002
    I don't know why people are surprised/complaining about the CPU.

    The 6700k and 4790k are the fastest quad core desktop chips Intel has to offer. We didn't use to have the option for the fastest chips in the iMac, I remember how excited I was last year when I saw Apple put the 4Ghz 4790k in there.

    Would I (and the majority of the target market for theses chips) be happier if Intel dropped the igp for 2 extra cores? Of course! But for a variety of reasons, that won't happen (at least not until Intel decides 6 cores is the new mainstream sweet spot).

    Would I be happy if Intel actually seemed to be trying to improve high end desktop performance? Hell yeah I would. But until either AMD steps ups its game or ARM chips start to encroach on the desktop space, it's unlikely. There's just way more money to be made in low power igp integrated chip sales.

    Is any of this Apple's fault? Not really. If you wanna be mad at Apple for this years iMacs there's plenty of reasonable reasons, from the lack of dgpus in the 4K, the rebadged AMD gpus in the 27, or shafting users by withholding the latest IO.
    the CPU choice however really isn't one of em...

    Unless of course you were hoping Apple would shift the high end to 6 cores :)
  17. mcnallym macrumors 6502a

    Oct 28, 2008
    The big problem I would see for Apple is that in the iGPU then Skylake doesn't offer Iris Pro. Whilst the 27" isn't affected as it doesn't use the iGPU. the 21.5" does. Thus you have the 21.5" iMac using Broadwell CPU's which the corresponding chipsets which don't support TB3/USB-C. iFixit teardown doesn't mention the chipset but would be surprised if is a 170 chipset and more likely a 97 so previous gen chipset.

    Would Apple offer the 27"iMac with USB-C/TB3 when not available on the MBP, and nMP yet, and also not on the 21.5" iMac, so would start getting a break in the boxes.

    I suspect that will need new rear design so Apple will wait till next iMac design refresh which also allows to get the nMP and MBP unto TB3/USB-C first.
  18. cynics macrumors G4

    Jan 8, 2012
    When thermal throttling is a contributing factor they will need to be compared INSIDE the iMac. A faster chip can be much slower if its thermal throttling vs a slower chip thats running cooler at 100%.
  19. Juliovalverde macrumors newbie

    Oct 5, 2015
    I thought the same and I posted it.

  20. cynics macrumors G4

    Jan 8, 2012
    Sorry to basically repost what you did. Sometimes I just read the OP and feel inclined to point out the obvious without reading any further.

    On that note, am I the only one that finds that thermal throttling in an iMac is inexcusable? If you built a PC and it did the same thing then you did it wrong. Usually this means you need to check your layout, fans and how well the thermal paste was applied. But you do not leave it like that, thats the point of running a stress test after a build. I understand that an all-in-one has its limitation but either the components need to be picked better to match the case or the case needs to be engineered to match the components.
  21. Juliovalverde macrumors newbie

    Oct 5, 2015
    Totally agree with you
  22. aevan macrumors 68030


    Feb 5, 2015
    Nope, there's a lot of people on these forums that constantly whine about it.
  23. cynics macrumors G4

    Jan 8, 2012
    True, I guess being on a tech forum there are plenty of people around that will point out the obvious.
  24. aevan macrumors 68030


    Feb 5, 2015
    That an ellegant All-in-one would have worse thermals than a desktop tower PC? Yeah, it is obvious, I guess.
  25. MoreAwesomeDanU macrumors regular


    Dec 4, 2010
    Lol. The day apple puts usb c ports only in these iMacs, millions of people are gonna bitch about the lack of USB ports on a desktop computer.

    And when they don't, people bitch about not having it.

    The Internet is hard to please

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