iMac 21.5" Late 2009 (10,1) - CPU Upgrade E8600

Discussion in 'iMac' started by AphoticD, Nov 22, 2017.

  1. AphoticD, Nov 22, 2017
    Last edited: Nov 22, 2017

    AphoticD macrumors 68000


    Feb 17, 2017
    I just wanted to report that after following information found on this forum and the always amazing walkthroughs at, I have upgraded my base-model iMac 21.5" (Late 2009);

    FROM Intel E7600:
    • 3.06Ghz Core 2 Duo
    • 3MB L2 cache
    • 1.06Ghz system bus
    TO Intel E8600:
    • 3.33Ghz Core 2 Duo
    • 6MB L2 cache
    • 1.33Ghz system bus
    Screen Shot 2017-11-23 at 10.39.47 am.png
    It may not seem like much, but it has made a noticeable improvement. I think the double sized L2 cache, 10% increase in clock speed (x2) plus the 20% improvement on the system bus all add up.

    Overall the CPU upgrade is a simple case of follow the steps. Despite being marked as "Very Difficult" on iFixit, it just took a while to get through the 42 teardown steps and then the refit. It was a good chance to meticulously clean out the internal components and fans as hundreds of dust bunnies had decided to take permanent residence inside the 8y/o flat mac. The CPU change was also an opportunity to replace the aging thermal paste and renew with silver.

    While upgrading this iMac, I also installed a Kingspec 256GB mSATA SSD (connected at full 3.0Gbps speed on the MCP79 SATA bus) and it's 4GB of RAM is due to be upgraded to 10GB later in the week (2x4GB going in, 2x1GB coming out).

    The LGA775 socket CPU upgrade was at a total cost of AU$25 (free shipping) from China. If I had found a reasonably priced Core 2 Quad with a 65w TDP (like the Q9550S), I would have tried that, but they are still selling for more than AU$100 and there have been zero confirmations of a C2Q CPU working in the iMac, so I took the economic option and not the gamble.

    It's a shame that this base model iMac didn't include the MXM GPU upgrade slot like it's Radeon-equipped brothers. The circuitry is on the logic board, but the slot is not fitted, which means this model will never be Target Display Mode capable and is stuck with the not-so-bad Nvidia 9400 GPU forever.

    The iMac runs well with High Sierra and overall, this is an improvement on an already solid model iMac and for the most part appears to run pretty cool. CPU temp is currently sitting at 38°C after running through Geekbench (with an ambient temperature of 27°C).

    (Out with the old - E7600)

    (In with the new - E8600). [CPU Macro-shots for @LightBulbFun ]

    An interesting story of this relatively large-sized CPU's endurance (And possibly part of the free shipping service) included after taking the slow boat across the Pacific Ocean, the postman when riding past my house on his motorbike decided to deliver the goods with a flick of his wrist, flinging it through the air like a Frisbee. I heard a smack on the front door and walked out to find the little bubble wrapped CPU sitting on the tiles with it's Chinese shipping labels looking up at me. The swift postie was nowhere to be seen.

    Screen Shot 2017-11-16 at 9.38.08 pm.png
    (Geekbench 2 (32-bit) score before @ 4316)

    Screen Shot 2017-11-22 at 7.50.21 pm.png (Geekbench 2 (32-bit) score after @4714)

    Screen Shot 2017-11-22 at 7.45.15 pm.png (And Geekbench 4's uploaded scores comparing the two).

    I know it's not much in the world of iMac Pros, but I thought it would be good to share and show that there's plenty of life in these Macs and at a fraction of the cost of a new Mac.

    Total expenses for this 2nd hand machine:
    • iMac 21.5" Late 2009 - AU$145 (sold as "faulty" - discovered the fault was just a dead WD 500GB HDD)
    • 256GB mSATA SSD - AU$120
    • mSATA adapter - AU$5
    • E8600 CPU - AU$25
    • 2x 4GB 1067Mhz DDR3 SODIMMs - AU$75
    • macOS High Sierra - Still free, even though this iMac would have originally shipped with Snow Leopard.
    Grand total: AU$370 (inc shipping) .. Approx US$280.

  2. redheeler macrumors 604


    Oct 17, 2014
    The Core 2 Duo is often dismissed as underpowered compared to the Core i5/i7, but in reality a better Core 2 Duo such as this, while no speed demon, is still good enough for the basics. Nice to see that everything worked out for you in this upgrade, and it shows there is a relationship between upgradability and longevity of a Mac.

    Slightly different in the case of my 11-year-old iMac 6,1, as it came out of the factory maxed-out with the highest CPU it will take (Core 2 Duo T7600 2.33 GHz). I did however upgrade the RAM from 2 GB to 4 GB (3 GB usable), as well as the original HDD with an SSD, and that made a huge difference running OS X Mountain Lion.
  3. AphoticD thread starter macrumors 68000


    Feb 17, 2017
    It runs surprisingly well with High Sierra on it's beautiful, bright LED-backlit IPS display. Apps fire instantly with absolutely no lag, despite only having 4GB of RAM (more to go in shortly). Cold boot from chime to desktop is 25 seconds flat. Siri and all of the other features are instant as you'd expect on a new machine. Firefox Quantum also runs beautifully. Everything runs cool with max internal temps around 50°C at the MCP heatsink (with zero fan ramping). It goes to show how software optimisations can make existing hardware shine.

    The real bottleneck on this iMac is that at the standard resolution (1920x1080) the integrated Nvidia 9400 GPU doesn't provide that super-silkiness you get from newer hardware. It's totally acceptable and not jerky or stuttering, but there is a noticeable improvement in overall UI framerates when the resolution is dropped down to 1280x720. THEN it feels like a (60fps+) zippy-fast new iMac.

    One thing I feel is missing from this generation of iMac is a sleep indicator light. It's odd to have no visual cue for whether it is asleep or powered off.

    But despite these (very) minor quibbles, I can see the late '09 iMac will be in my arsenal of Macs for many years to come.

    The 6,1 is still a great machine with only marginal real-world-use limitations. There are still quite a lot of apps with 10.7+ support in active development, so at least 10.8 is not on the bottom-rung (yet).

    Your machine has the smooth white perspex look of a classic G5 iMac, but it's not stuck on Leopard, has more than twice the processing power and probably runs much cooler than it's big-endian sibling.
  4. elf69 macrumors 68020


    Jun 2, 2016
    Cornwall UK
    I'm thinking of doing CPU upgrade (I have CPU already) to a 7,1 or 9,1 20"

    once done I can run Sierra on it.
    I like the ally iMacs but not a fan of the white models.

    my current 7,1 iMac is ok but even with 6gb ram it pauses now and then and beachball.
    not done SSD yet but looking at possibly buying a 9,1 iMac.
  5. AphoticD thread starter macrumors 68000


    Feb 17, 2017
    A good way to determine whether the cause of the pausing/beachball is RAM or HDD related;

    Open Activity Monitor and observe the memory pane. If you are seeing page outs then the 6GB is not enough to do what you’re asking of it and the pause is occurring when the system is swapping memory out to the HDD.

    It would be much more likely though that there are zero page outs and the beachballing is due to the HDD reaching it’s mechanical end-of-life.

    Open Console and see if you spot any disk I/O errors during the pauses.

    I would imagine installing an SSD and clean installing the OS will bring a complete fresh breath of life back into your iMac.

    6GB of RAM should really be plenty for what the 7,1 is capable of.
  6. redheeler, Nov 24, 2017
    Last edited: Nov 24, 2017

    redheeler macrumors 604


    Oct 17, 2014
    Probably what I like the most about it is the matte screen, as the 2007-2011 iMacs get noticeable reflections in a bright room, while this one does not. Panel quality is similar to the 23" Apple Cinema Display, if not slightly better - very nice for a screen from 2006 (though not LED-backlit and contrast ratio is bad compared to more modern ones).

    I recently came across a brushed metal theme for Mountain Lion, and since this Mac would've come with Tiger originally, I figured why not. :)
    Screen Shot 2017-11-24 at 8.51.56 PM.png
  7. 06tb06 macrumors regular


    Sep 12, 2017
    2,711 miles from Apple Campus
    I remember the Core 2 Duo chips well. Hard to believe they're almost eight years old now. Pretty good performance per watt back in the day, especially over the P4s they were meant to replace. As Steve Jobs put it, "These things are screamers." Nice to see your upgrade went without a hitch, new CPU detected.

    I'll give my iMac five years or so before I decide wether or not I want to do a teardown and upgrade the internals. If so, I'll probably go for the i7-7700, 32GBs of RAM, and maybe 512GB SSD.
  8. AphoticD thread starter macrumors 68000


    Feb 17, 2017
    Nice "retro" theme. This is how brushed metal was meant to look.
  9. redheeler macrumors 604


    Oct 17, 2014
    Yes, it's a great theme, and especially goes well with this older pre-aluminum/glass iMac. Too bad there aren't any themes like this available for High Sierra, but I did successfully build a set of Aqua-inspired traffic light replacements that look good on both my Retina and non-Retina Macs.
  10. trifero macrumors 6502

    May 21, 2009
    Thanks for sharing. Ordered a CPU for 15 euros.
  11. AphoticD thread starter macrumors 68000


    Feb 17, 2017
    Nice. Let us know how it goes.

    My iMac is still going strong with the upgraded CPU and keeps cool most of the time. It now has 10GB of RAM, so plenty of elbow room to keep up with High Sierra. Just don't ask the 9400 GPU to playback 4K video in realtime.
  12. LAHegarty macrumors regular


    Aug 17, 2013
    York, UK.
  13. mail4ng macrumors newbie

    May 28, 2018
    Just signed up to get in touch with you about this topic. I hope you are still operating this upgraded iMac.

    My question is specifically about a CPU feature. I love my 27" iMac (late 2009), with SSD drive and 16 GB RAM. CPU power is not essential to me, so it's still a more or less perfect desktop machine.

    The only thing I'm badly missing is support for Docker. As Docker relies on specific CPU features, my hope is that a CPU upgrade could help me out.

    In case you are still operating the Mac in question, could you please execute the following in the terminal and hopefully tell me that the output is 1. :)

    sysctl kern.hv_support
    According to the Docker documentation it could serve as an indicator if Docker is supported by CPU or not.

    Many thanks in advance!
  14. AphoticD thread starter macrumors 68000


    Feb 17, 2017
    The sysctl output for the Hypervisor support is unfortunately 0.
    (kern.hv_support: 0)

    I don't think any of the Core 2 Duos had this feature - but I could be wrong.

    Software like Virtual Box, Parallels, VMWare Fusion and QEMU will run multiple VMs perfectly fine on this machine however, so maybe there is a technique to get Docker going inside a VM?
  15. mail4ng macrumors newbie

    May 28, 2018
    Sure. Running Docker inside a VM works perfectly fine. But it adds another layer of "virtualization" on top of the "virtualization". Will give sometimes headaches if you are mapping ports and/or shares from the Docker container, to the VM to the actual host. :)

    That's why I hoped to achieve native Docker by a CPU upgrade.

    Thanks for you reply
  16. Guy Clark Suspended

    Guy Clark

    Nov 28, 2013
    London United Kingdom.
    I have carried out the same upgrade in the past and have found there to be no appreciable performance gain.

    Later generation Intel Core 2 Duo CPU's continue to hold their own even in 2018.
  17. maxx.monopoli macrumors newbie

    Dec 19, 2018
    Hi AphoticD,

    I was exploring the internet looking for infos about upgrading the cpu of an old iMac 21.5" 10,1 (Late 2009) and I've found your great post.
    I have a couple of questions:
    1) has it been necessary any efi and/or firmware reprogramming after you've changed the E7600 with the new E8600?
    2) I've found a cheap Intel Core 2 Quad Q9550S, so I think I will give it a try. From the experience with your upgrade, do you think that upgrading to Q9550S could be flawlessly as well?

    Thank you.

  18. AphoticD thread starter macrumors 68000


    Feb 17, 2017
    Hi @maxx.monopoli ,

    The iMac picked up the new CPU without any EFI mods. My understanding was the E8600 was an Apple build-to-order option at the time this machine was new.

    I wasn’t able to find any confirmation that the Q9550S actually works in this machine, but if I recall correctly, the TDP is a match. It might be worth your while to try the Quad Core if you say you found a cheap one - worst case, the iMac won’t boot, you re-sell the CPU and put the E8600 in.

    Good luck!
  19. maxx.monopoli macrumors newbie

    Dec 19, 2018
    Hi @AphoticD

    thank you for your reply.
    I will try the Q9550S and I'll post the outcome.


  20. AphoticD thread starter macrumors 68000


    Feb 17, 2017
    Great! I am looking forward to hearing how you go. If it does work, I’ll be happy to know there is more expansion available for this (nearly) 10 year old Mac. :apple:
  21. highvoltage12v macrumors 6502


    Mar 27, 2014
    I am also trying this, but I don't think it will work without adding the Yorkfield's Microcode to the iMacs Rom and flashing it manually using an SOIC 8 clip. I just ordered a q8200s (cheap, will go higher if it works) and will report after Monday if adding the Microcode allows it to work.

    With an 85w TDP q8300 and Yorkfield Microcode, the iMac will at least beep when no RAM is installed which is an improvement vs no microcode and nothing happening. But it won't POST probably because of the 85w TDP.
  22. Ooze macrumors newbie


    Apr 24, 2019
    1/2 of SHATTERED
    Did we ever get a followup to this? A q9550s or similar Quad Core in a Late 2009 would be exactly what I'm looking for for my gtx 1060 project.
  23. highvoltage12v macrumors 6502


    Mar 27, 2014
    No injecting microcodes into the rom, trying 3 different core 2 quad CPU's etc never worked. I ended up putting an e8600 in it.
  24. LightBulbFun macrumors 68000


    Nov 17, 2013
    London UK
    one thing I have been wanting to try on one of these LGA775 iMacs

    is to try and install an LGA771 CPU, something like an X5270, which is a 3.5Ghz Wolfdale Chip :)

    (it might require microcode injection but thats fairly easy to do these days :) )

    sadly I dont have an iMac10,1 to experiment with
  25. ruben253 macrumors newbie

    May 2, 2019
    Hi, I've been looking at upgrading my 27" 2009 imac (in the hopes that it will be able to play 4k videos without lag, done the SSD and RAM already). Any indication whether this works? as the Q9550s is quite cheap now

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29 November 22, 2017