Core i5 3.6 GHz vs Core i5 Quad 2.8 GHz

Discussion in 'iMac' started by gonzo84, Jul 27, 2010.

  1. gonzo84 macrumors newbie

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    Jun 14, 2010
    #1
    I am sorry if such a thread exists already, i didn't find anything, so......

    Im just configuring the iMac I'd like to buy and am wondering about the difference between the Quad Core i5 and the dual Core i5 with 3.6 GHz.

    I'm not much of a video or sound editor, not even photos really,, some occasional gaming. I've noticed the 3.6 GHz is Clarkdale in 32 nm while the 2.8 Quad is Lynnfield with 45 nm.

    I tend to the Quad, simply because I don't really like something to be maxed out, which i assume is the case in a 3.6 GHz chip.

    I am confused and hope u guys can help me make a decision.

    Thanks a lot
     
  2. hleewell macrumors 6502a

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    Oct 22, 2009
    #3
    Well, it also depends on whether the game is written for dual core or quad core system. A Quad Core will always be faster than a Dual Core, technically speaking. But a dual 3.6 i5 can be faster in certain applications than a quad 2.8 i5.
     
  3. Hellhammer Moderator

    Hellhammer

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    #4
    Quad i5 goes up to 3.33GHz with Turbo. The CPU is not the bottleneck here, it's the GPU so there won't be huge difference between the games plus all upcoming games support quad core so future wise quad is better investment.
     
  4. Eidorian macrumors Penryn

    Eidorian

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    #5
    Lynnfield any day of the week over a 2 core, 4 thread Clarkdale.
     
  5. alent1234 macrumors 603

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    Jun 19, 2009
    #6
    the dual has 4MB cache and the quad has 8MB cache. game performance will be so small you won't notice it.

    the sweet spot for this refresh seems to be the higher end 21.5" model. last time it was the lower end 27" which is over priced this time
     
  6. dolphin842 macrumors 65816

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    #7
    If you're not going to be encoding video or running multiple virtual machines on a regular basis, the dual-core i5 should be fine.

    But Eidorian's right... the quad-core will certainly be faster... depends if you want to put out the extra cash though.
     
  7. gonzo84 thread starter macrumors newbie

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    Jun 14, 2010
    #8
    Thanks guys, you have been a huge help.

    21,5'' core i5 would be nice, but i am concerned if the gpu will serve my future needs. 5750 seems to be noticably faster then 5670 i think.

    So to sum up, the concensus seems to be Lynnfield Core i5 Quad is better if you want to spend the extra cash. Even though Lynnfield is manufactured in 45 nm? I guess I am overthinking it, anything will be better then my Merom, right? :)

    Thanks
     
  8. stroedel macrumors newbie

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    Jul 27, 2010
    #9
    another question:

    i3 anno 2010 vs i5 anno 2009

    will there be a big difference ?
     
  9. Hellhammer Moderator

    Hellhammer

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    #10
    The manufacturing process doesn't really speed it up. Lynnfield iMac gets you the better GPU as well
     
  10. Eidorian macrumors Penryn

    Eidorian

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    #11
    The Core i5 750 wins. There will never be a Core i3 (Clarkdale) that's faster than the Core i5 750.
     
  11. Hellhammer Moderator

    Hellhammer

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    #12
    Yes, i5 is a lot faster as it's quad core
     
  12. stroedel macrumors newbie

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    Jul 27, 2010
    #13
    tnx for replys...
    and what about the i3 versus the "old" Intel Core 2 Duo E7600
    cause difference here is 1729 € vs 1499€
     
  13. Hellhammer Moderator

    Hellhammer

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    #14
    Depends on what you do. You won't notice much, if any difference if you just browse on the net but if you do something CPU intensive like video encoding, the i3 is better
     
  14. stroedel macrumors newbie

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    Jul 27, 2010
    #15
    if im not a gamer, and if i only do video encoding once a month..
    im thinking on getting dual core + 4 GB extra ram !
    pff, they didnt make it easy ...
     
  15. dolphin842 macrumors 65816

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    #16
    I'll be running some more Handbrake encoding benchmarks once I get to the Apple Store, but here are some results from running it on the last-gen iMacs and current-gen MBP:

    [EDIT: scroll down the page for updated benchmarks]
    i5 750 (2.6 GHz x 4): 62fps [EDIT: disregard this, I had inferred it from a quad-core i7 reading]
    Core 2 Duo (3 GHz x 2): 31fps
    i7 (from MBP, 2.6 GHz x 2): 37fps
     
  16. Eidorian macrumors Penryn

    Eidorian

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    #17
    It doesn't sound like Turbo Boost is in action on that Core i5 750.
     
  17. dolphin842 macrumors 65816

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    #18
    Hmm... I was running Handbrake in the same way on each machine (High Profile x264, RF 28). The quad-core i7 got ~67fps. Are the other figures in line with what you'd expect?
     
  18. Eidorian macrumors Penryn

    Eidorian

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    #19
    It appears that I was incorrect. You were perfectly in line.
     
  19. freiheit macrumors 6502a

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    California
    #20
    Looking forward to your new i5 / old i5 numbers in Handbrake

    It's a shame for them to call that overpriced dual-core an i7. It's a crying shame and gives the i7 a bad name. Looking forward to your reports on the new iMacs, especially the dual-core i5 versus the quad-core i5 since both technically provide 4 threads. I suspect real cores will always beat virtual ones, but over time virtualization/hyperthreading should become more refined and maybe the line will blur.
     
  20. RAM3Zero macrumors newbie

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    May 27, 2010
    #21
    Just ordered!

    As a direct result of this thread, I finally placed my order for a 27" quad i5 (with trackpad, I couldn't resist). Was considering going low-end but knew in the end I wouldn't be satisfied. I've been itching to switch over to mac for a really long time now and finally placing the order is quite freeing.

    Thanks to Hellhammer, TMRaven and Eidorian (plus others) for their solid input over the past 6 months. I've been following your posts regularly and you've answered my unasked questions and provided great data. Should arrive between August 3rd-10th in Canada, will keep you posted.

    R.
     
  21. dolphin842 macrumors 65816

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    #22
    Alright, just got back from the Apple Store. There weren't any i5 3.6GHz (dual-core) or quad-core i7's on display, but I got stats on the rest. Here they are along with all my other data:

    Handbrake x264 test (High Profile, 28 RF, 720x480 DV source file @ 60fps, anamorphic loose w/ 40px auto-cropping on left and right):

    13fps: 1.83 Core Duo (original intel iMac, my current machine:rolleyes:)
    25fps: 2.6 Core 2 Duo (Mac Mini Server)
    31fps: 3.06 Core 2 Duo
    37fps: 2.66 i7 (dual-core, MacBook Pro)
    41fps: 3.06 Core i3 (dual-core)
    43fps: 3.2 Core i3 (dual-core)
    65fps: 2.8 Core i5 (quad-core)
    67fps: 2.8 Core i7 (quad-core, 2009 model)

    A few notes for this particular workflow:
    - The move from Core 2 --> i3 yields about a 32% performance increase at identical speeds for the dual-cores. What a difference an architecture can make:cool:.
    - The flip side of the previous point: Whereas moving from to 2 to 4 cores yielded an essentially linear performance increase in last year's models (~100% when the jump was from a core 2 to a core i5), this year the extra cores only get you a ~50% increase in performance.
    - The speed bump from 3.06 i3 --> 3.2 i3 is rather minimal; in this case, you'll only want to pick the faster model if you want the newer ATI graphics and/or the extra 500GB of internal storage. For single-threaded applications, I believe the 3.2 i3 has turbo boost, which may make a bigger difference.
    - Hyperthreading (quad-core i5 vs. i7) yields only a 3% speed increase, likely because x264 is multithreaded and maxing out all physical cores, leaving little downtime for hyperthreading to be of use.
     
  22. freiheit macrumors 6502a

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    California
    #23
    You are wonderful!

    You are wonderful! Thank you so much for posting this. Does the Apple store seriously let you go in and put your own data on their systems to try stuff out? I mean, you had to have installed Handbrake and attached a drive with your data and stuff. What DON'T they let you do?

    It's too bad you didn't get to benchmark the dual-core i5. I'd love to see how it compares to the quad-core and how much you really get over the i3 running 400MHz slower. I would prefer to buy a quad-core, but the 27" screen is far too big and high resolution for me, so the top 21.5" is where I'd be buying unless the 27" with i5 shows a significant performance boost.
     
  23. dolphin842 macrumors 65816

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    Jul 14, 2004
    #24
    No problem... I'm in the market for a new Mac myself so I figured I'd share what research I've done so far :).

    Yeah, the retail stores let you mess around with the Macs quite a bit. I've not had any employees ask what I was doing, though one time they did quickly reboot the machine after I left :rolleyes: (I assume it has a default disk image that it reverts to). As for file transport, Handbrake.app and my test file fit on a 1GB flash drive, so it's easy to just hook up and drag both to the desktop.

    My guess is that the performance increase going to the 3.6 i5 will be pretty linear. Both cores are taxed with x264 encoding, so even if the turbo boost is more substantial on the i5, there won't be much opportunity to use it (similar to hyperthreading's limited usefulness in this scenario).

    So for the 3.6 i5 you'd probably be in the 48fps range or thereabouts. If that's the case, then the move to quad-core would give a performance increase in the neighborhood of 35%. As I mentioned above, the speed bump going from dual-core-->quad-core is less pronounced this time around due to the lower-end iMacs finally getting the new i-series architecture. So unless you plan on encoding videos fairly regularly, the extra cost of the 27" might not be worth it.
     
  24. Will : Hi ! macrumors member

    Joined:
    Apr 1, 2006
    #25
    HandBrake's High Profile preset enables 2 poorly-threaded filters (decomb, and more importantly detelecine) by default.

    Edit: Also, DV at 60 fps? Are you sure it's not 480i60 (60 fields per second)? That's likely causing some more time spent in the filters vs. actually encoding in x264.
     

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