New 21.5 iMac - Unsure of whether a processor upgrade is best?

Discussion in 'iMac' started by nickosbad, Sep 7, 2014.

  1. nickosbad macrumors regular

    Feb 16, 2009
    Hi All

    As discussed in one of my other threads (fusion vs SSD), I am about to order a 21.5" iMac to replace my old 3.06 i3 iMac which sadly is no longer with us!

    The main use for the machine is to act as a host for all of my iTunes music and media, iPhoto work (occasional Photoshop), web browsing but MAINLY Handbrake Encodes

    I make copies of my Blu-Rays and encode them twice (one in ATV3 1080p format and one in 720p iPad mini Retina format)

    My old machine would run at around 6fps for the 1080p versions which would mean leaving it running overnight for a single encode which i don't like to do

    I am already upgrading to a 256GB SSD for speed as all of my movies are stored externally as I have over 1.5TB at the moment but am wondering if it is wise to max out the processor whilst I can

    I believe that the i7 will have a huge benefit using Handbrake over the i5 (which should also be no slouch compared to my old iMac) but am i right, will the differences be severe??

    The difference between the two for me is around £300 (2.7 i5 vs 3.1 i7)

    I am going to order tomorrow to take advantage of the iTunes voucher so am hoping that they don't announce some upgraded to the iMac line soon!!!

  2. cebseb macrumors regular

    Feb 21, 2011
    Well, the increase in performance doesn't really compute to a significant number. It hovers between 7-10%. However, that difference translates into a 1hour deficit when it comes to an 10 hour encode run. Since most professionals (including myself) equate time to money, I am more than happy to fork out the cash for minute increments of speed boosts when I can.
  3. nfable macrumors regular


    Apr 9, 2007
    I'll echo cebseb: if a faster rig lets you get on to other things by saving you time, it's worth it.

    But you have to ask yourself: how often do you do this? Once a week? Month? Day? Every chance you get?

    If the frequency of the need warrants it, plop down an extra $1k USD for a Mac Pro; or wait in the bushes for a refurb MP to save on expense.

  4. yjchua95 macrumors 604

    Apr 23, 2011
    GVA, KUL, MEL (current), ZQN
    In hyper threaded tasks, the 3.1GHz can be around 30-40% faster than an i5.

    And since you're comparing to the 2.7GHz i5-4570R, the difference is even larger.

    Comparing the 2.7GHz with the 3.1GHz i7 (my machine):

    The difference is 37.5% between the two.

    Plus, the i7 variant comes with a GT 750M card, which is far superior in rendering and gaming.

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