iMac 27 i5 or i7

Discussion in 'iMac' started by 5piN, Dec 11, 2010.

  1. 5piN macrumors member

    Dec 11, 2010
    Okay guys i'm new to the whole Mac scene so need some advice

    I’m looking to buy either the i5 or i7 with 2tb and 4gb ram but can't decide if the i7 is worth the extra £160.

    I'm going to try my luck at gaming using bootcamp, other than that it’s the usually web/movies etc....

    Looking at the various sources the GPU looks like a bottleneck but I’m think more in terms of like in a years time when more games might use extra cores and multithreading.... is the £160 really worth the future proofing..

    Also is there any extra heat and noise? due to hyper threading?

    Alternatively should i hold out a few months as I’m sure there must be a refresh in a few months with Lion coming?
  2. rkaufmann87 macrumors 68000


    Dec 17, 2009
    Folsom, CA
    Wow, no one has asked that question in at least an hour.

    Try doing a search, you will find more threads and answers than you can read.
  3. mulo macrumors 68020


    Aug 22, 2010
    Behind you
    the i7 has hyperthreading and supports tripple channel memory.
  4. dndlnx macrumors 6502


    Dec 9, 2010
    £160 is about 250 US Dollars. So they rip you guys even more, eh? :rolleyes:

    I dont know about waiting for 10.7, it wont be here until mid-2001 (summer).
  5. SandboxGeneral Moderator emeritus


    Sep 8, 2010
    Now Lion is WAY ahead of it's time! :D
  6. dndlnx macrumors 6502


    Dec 9, 2010
  7. Wassim macrumors newbie


    Nov 10, 2010
    i recommend you get the i7, I read that it's almost two times more performant then the i5 and I've had mine for about a month it's amazing.
  8. josh1231 macrumors regular

    Feb 24, 2010
    Unlike the last poster, I haven't seen anything showing more than a 20-25% increase in speed for the I7. That being said, 20% increase in speed is easily worth $250 in my book. I bought the I5, but if I were you I'd get the I7.
  9. easepease macrumors regular

    Feb 9, 2010
    I only notice a difference when ripping movies in handbrake, rendering videos, and then finally I will sometimes see a difference when playing mkv files (blue ray) and doing other things at the same time.

    If you don't do any of those things i mentioned above, mainly rendering videos you will not notice much if any of a difference
  10. 5piN thread starter macrumors member

    Dec 11, 2010
    That 20% gain is mostly in applications I don’t really use. The real tuff one is if future games that utilise multithreads will see speed increases?
    I generally tend to upgrade about every 3 years so it’s trying to figure out if the extra $250 will be of any benefit ……
  11. Spudracer macrumors 6502

    Oct 4, 2009
    Well, I just bought the 27" i5 Quad because the data I saw showed very little difference in benchmarks between the i5 and i7 quad core processors in the new iMac's in real world tasks. And while some of Intel's i7 processors use 3 channel memory, both the i5 and i7 that Apple uses in the iMac employ only dual channel memory. They are a step below the "900 series" architecture at the top of Intel's Core i processor lineup. The two processors are the same except for
    1. Quad Core i5 lacks hyperthreading whereas the Quad Core i7 has this feature.
    2. Clock speeds
    3. Turbo Boost overclocking speeds.

    In addition, everything I've read indicates that there are very very few applications that people actually use which can currently make use of four physical cores let alone an additional four virtual cores. Maybe in 4-5 years the application landscape will be drastically changed. But by then, I'll probably want to dump the iMac for a two generation leap forward in processor technology. I say save the £160 or $200. Personally, I never take Apple up on processor upgrades as the difference between their top standard configuration and the build to order upgrade never seem to offer much value in the real world. The only way I'd consider the i7 right now is if you're going to be rendering video all day every day or if you have some other specific need that an i7 can really address. Otherwise you're just buying bragging rights. There is no such thing as future proofing with computers. Moore's Law.....ain't been broken yet!

    Better to invest in a SSD and memory for bang for the buck.
  12. tehpwnerer19 macrumors member

    Mar 4, 2010
    I opted for a refurbished 2010 27" i7 for $1900 and say it was well worth it.:apple:

    From barefeats:

    The 'mid 2010' iMac Core i7, is as much as 45% faster than the Core i5 for 10% more cost.
    The Core i7 is as much as 104% faster (twice as fast) as the Core i3 for 29% more cost.
    The Core i5 is as much as 41% faster than the Core i3 for 18% more cost.

    To put it another way, going by the Cinebench rating,
    you pay $400 for each rating point on the Core i7,
    you pay $526 for each rating point on the Core i5, and
    you pay $629 for each rating point on the Core i3.

    Want real world? In the After Effects render test,
    the Core i7 beats the Core i5 by 33%, though costing 10% more, and,
    the Core i7 beats the Core i3 by 42% though costing 29% more.

    Want more real world? In the iMovie "export to HD" test,
    the Core i7 beats the Core i5 by 20% though costing 10% more, and,
    the Core i7 beats the Core i3 by 34% though costing 29% more.

    I say the top iMac model is the best buy.
  13. dndlnx macrumors 6502


    Dec 9, 2010
    I thought i5 also had the turbo boost.
  14. JBunkers macrumors member


    Sep 20, 2008
    In the middle
    Get the 3.6 i5

    The dual-core i5 does have turbo boost, the quad-core i5 does not.

    I would recommend getting the dual-core i5 for the following reason. Multiple cores sounds really awesome, until you stop to realize that most applications on the market today do not even utilize more than one core at a time. This is true for both Mac and Windows machines. Basically, the megahertz myth has morphed into the multi-core myth, it is essentially a marketing ploy to sell more expensive computers, and more of them. Even software vendors such as Adobe have not optimized their applications (such as Photoshop) to take full advantage of multiple cores. Since Grand Central (part of OS X 10.6 Snow Leopard to make it easier for developers to program their applications to take advantage of multiple cores) was introduced just last year, it will be a while before we start to see the benefit of a lot of cores in mainstream applications.

    You said that you generally upgrade every 3-4 years? Then I would save some money on this purchase by going with the dual-core i5, and by the time you want to upgrade again we will (hopefully) have some applications and games that are designed to exploit the 6, 8, or 12 cores you'll be able to get in an iMac by then. Put the money you save towards an external backup drive, or a new camera.
  15. Bobbytoad macrumors member


    Nov 18, 2010
    I was in exactly your shoes a few weeks back, and ended up getting an i7 the following reasons helped my decision

    Use and sign up to Quidco which will give you over £50 by clicking through and buying from the Apple Store online.

    Secondly I got mine from the Apple Refurb Store - - you may have to wait a few days for one to come up (with Christmas I wouldn't think it would be too long) mine cost £1529!! they only advertise standard configurations but many buyers have found their new refurbs have some hidden goodies free of charge mine gave me a gift of 8gb ram and a 2tb of HD - all are covered by 1 year Apple warranty and you can sign up for Apple Care also. Great service from Apple computer arrived next day.
    Thread on refurbs -

    hope this helps and saves you a few quid!
  16. Spudracer macrumors 6502

    Oct 4, 2009
    It does. The quad core i5 does have turbo boost it just doesn't over clock to the same speeds as an i7 which generally have a higher normal clock speed to begin with. That's all I meant. The difference is minimal. Sorry for the confusion.
  17. Winni macrumors 68040


    Oct 15, 2008

    When you ask the Linux kernel hackers, you will hear that HyperThreading in many real life situations actually decreases the performance instead of improving it.

    I cannot answer whether the i7 produces more heat and noise than the i5 because I have never seen an i7 iMac in a controlled environment that would allow me to make such a judgment call. However, I would expect the i7 to be noisier.

    By the time you might see games that require four or more cores to run properly, your iMac will be at least five years too old to even run them. In other words: There is no "future proofing" by buying something TODAY that MIGHT be of use TOMORROW.

    There are only a fistful of games out there that THEORETICALLY benefit from DUAL core CPUs - one core is being used for the game loop, the second core for physics calculations. But the truth still remains that the game would still run faster on one fast core than it would on two slower cores.

    So where do you actually get something from those four or more CPU cores? Processing of RAW images. Video editing. DVD ripping. Running multiple virtual machines. When you do stuff that CAN take advantage of parallelization - but games traditionally don't.

    If gaming is your focus, don't buy an iMac. Don't buy a Mac at all. You'll get more bang for the buck elsewhere, and you'll be needing a Windows system anyway - almost nothing runs natively on OS X, and if it does, it will run slower than the Windows version, and since those are games we are talking about, the difference -- IS -- significant. For example, the OS X version of Left4Dead 2 plain and simple SUCKS on my 27" iMac i5. You really want to play this on Windows on that machine.

    If you still want to buy Apple hardware, then buy a Mac and also buy a console for your gaming needs. I recommend an Xbox 360 - it's the best investment in gaming hardware that I ever made. But if you go for this combo, then an i7 CPU definitely won't matter. At all. And the funny thing is that for the price difference between the i5 and the i7 CPU, you can almost buy the Xbox... ;-)
  18. Spudracer macrumors 6502

    Oct 4, 2009
    I say you don't know what you're looking at. Barefeats is a shoestring operation. The "testing" you're quoting wasn't done in a controlled fashion in a lab. They took inputs from their "mad scientists" (readers on the web) and cobbled the results together with their own test of a single iMac. Hardly rigorous testing under controlled conditions. And those speeds you're so proud of. Barefeats is quoting raw processor performance. Unfortunately, your processor has to work with the rest of the components in an iMac in order to work at all. Since the two machines share the same RAM, bus, hard drive, and video card, your raw i7 performance becomes meaningless or at least a bit strangled by other system components. I.E. a 50% better processor score rarely translates into 50% less time to finish a job in the real world.

    Take a look at this test from macWorld.

    On the Cinebench test they show 1:09 for tthe Core i5 vs 0:54 for the Core i7 (with an SSD). That's a 28% improvement. Not bad but, hardly the 45% improvement the Barefeats processor score represented. Now take a look at the Handbrake times. The Core i5 completed the task in 1:01 while the Core i7 took a lazy 2:49. That's 277% longer than the Core i5. Why? It appears the Apple has spec'd a couple of supliers for the new iMacs and the i7 equipped machine had a Hitachi drive while the i5 machine had a much faster Pioneer drive. See, components other than the processor become the critical path constraint in the overall system design. Why pay for a faster processor when the processor is not the problem?
  19. Sdashiki macrumors 68040


    Aug 11, 2005
    Behind the lens
    Quad-core may not be able to dump all 4 cores at one application or game right now...but I sure as hell can run a bunch more apps than my DualCore setup without any beachballs or hiccups.

    Even with slightly less RAM right now. More on the way!
  20. 5piN thread starter macrumors member

    Dec 11, 2010
    Refurb store was my first port of call but unfortunately you cant take advantage of the financing special offers currently running!

    I already knew about Quidco so was planning to do that!

    I def want 2tb too and refurb is going to be pot luck on getting any hidden goodies but you def did pretty well :eek:
  21. tehpwnerer1918 macrumors newbie

    Dec 13, 2010
    Tomshardware, amongst many other sites, has done extensive testing on whether Turbo Boost and Hyper Threading have an effect on normal computing, and they do. If you are doing single-threaded tasks TurboBoost shuts off unused cores and overclocks the cores in use, therefor making your 2.93 GHz i7 CPU up to a 3.6 GHz CPU. Hyper threading also turns your quad core CPU essentially into an 8 core CPU. The quad core i5 only supports TurboBoost, and the dual core supports both HyperThreading and TurboBoost, but essentially only becomes a quad core.

    Here is a comparison of the 2.93 GHz i7 4c/8t, 2.66 GHz i5 4c/4t and 3.33 GHz i5 2c/4t, obviously the results would be a little different w/ the 2.8 i5 4c/4t and 3.2 GHz i5 2c/4t, but they should yeild similar results. You can see that in most cases the i7 IS AT LEAST 50% faster than the dual core and quad core i5, and in some cases 100% faster. You can also see it greatly helps improve the FPS in video games.,2416.html?prod[4481]=on&prod[4483]=on&prod[4486]=on

    Also, of the 1000+ CPUs on the 2.93 i7 comes in at #28 w/ a score of 6061, the 2.8 i5 comes in at #162 w/ a score of only 1003, and the 3.2 at #144 w/a score of 3114. It's quite obvious that the i7 is worth the small amount of money extra that it costs, even if it only turns an i5 30 second job into a 15 second job, take that every day that's an hour and a half of your year saved up ;)

    Please disregard spudracer's lack of knowledge.
  22. 5piN thread starter macrumors member

    Dec 11, 2010
    Well I wouldn't say I game enough to warrant a console! ... I'm a casual gamer at best, it might be months before I game but when I do play I prefer the experience to at least be half decent!!

    I currently have a shuttle box and its damn noisy, so that's what attracted me to the iMac's .... quiet and that great screen! ... with the bonus of also being able to game .... my current machine is by no means cutting edge .... Shuttle SX38-P2 Q6600 OC to 2.52 with a Geforce 8800 GTS 512 but does me okay for most games .....I'm struggling to find a replacement system that has the same small form factor but with out the damn noise! ... hence the MAC! ... Not to mention the i get the best of both worlds.... try out OS-X but still have Windows 7!
  23. tehpwnerer1918 macrumors newbie

    Dec 13, 2010
    On a side note, I use my Mac to do some gaming as well, StarCraft 2 being the most intensive one graphics wise, and I can play it in full resolution with everything maxxed out with no problems. I do own a console and if they don't make a game for Mac OS X I will buy it for my console, I won't support Windows. Check out Steam, there are a lot of great games coming to Mac thanks to them, and the Core i7 coupled with the 5750 will have no problem conquering them.

    Just a warning: Once you go Mac you never go back...
  24. Spudracer, Dec 13, 2010
    Last edited: Dec 13, 2010

    Spudracer macrumors 6502

    Oct 4, 2009
    But please do focus on the half truths and misinformation being quoted by ehpwnerer1918.

    Since Tom's Hardware (good site BTW) doesn't have information for the both Core i5 760 and the Core i7 870 you really can't state anything about relative performance other than that the i7 should be faster. How much faster? We won't know until they post the i5 760 results. The relationship of core count and clock speed to real task speed is anything but a linear relationship. There are many other system components that constrain the processor not to mention the software design of a given application. Faster rendering is nice but no computer today is fast enough to get me to sit there watching it grind out an hour of HD video. No thanks, I set that up at 11:00 and wander off to bed with a nice book. If it finishes in 5 hours instead of 7 it's irrelevant. It'll be done when I wake up. Now if it could finish in say, 30 you're talking!

    As for your quote of Passmark scores, please learn to read more carefully Ace. The Core i5 760 is #64 not #162 and it's CPU score is 4572 not 1003. Man, I would think a simple sanity check would have told you that you were way off base. Apparently not. Reading is fundamental. Comprehending is critical too. Paying attention never hurts either. And, once again those CPU scores in a vacuum don't tell you how a system will perform as a whole.

    And BTW, the passmark score for the Core i5 760 is 4572 vs the Core i7 870 score of 6061. That's a 32.5% difference. Not bad, but a far cry from the 50% - 100% you're claiming. Will all of that 32.5% difference show up in real world work? It's doubtful. I'm sure the i7 will shine in some very specific tasks but for most people the difference wouldn't be noticable on most tasks.
  25. 5piN thread starter macrumors member

    Dec 11, 2010
    Is anybody with bootcamp able to post the results of the Windows 7 Experience Index on the i5 or i7 ? with ATI Radeon HD 5750 so mid 2010... i cant find any similar post on the forum...

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