iMac 8.1 SSD upgrade questions

Discussion in 'iMac' started by macstatic, Oct 15, 2013.

  1. macstatic macrumors 6502a

    Oct 21, 2005
    My wife complains that her iMac 8.1 (early 2008) is running slow. That and the fact that I've read iMacs overheat easily given the limited space inside, thereby shortening its life, has led me to suggest I replace the hard drive with an SSD. Should accelerate lots of stuff and do away with the heat. Some questions before I proceed though:

    1) what kind of 3.5" to 2.5" adapter do I need? There are different kinds and I hear that not all such adapters fit in all computers.

    2) There are many discussions on the hard drive temperature sensor. Apparently the stock hard drive has a sensor built-in which SSDs don't. I read that most people just short the sensor cable, then use software to run the fan at a certain speed.
    I'd rather have the fan adjust itself automatically depending on the internal temperature. Isn't this possible any longer with an SSD installed? How about the other fans (CPU etc.)? Won't they react to temperature changes either?

    3) Anything else I should keep in mind before going ahead?
    I haven't decided on which SSD brand/model to get. Personally I have a couple of Samsung 830 SSDs in my Mac Pro and chose them because of their proven reliability. Alas they're no longer available, but I prefer a reliable and long-lasting SSD instead of one which performs a little faster but needs replacing after a couple of years. I'm sure just about any SSD will give the performance boost she's looking for anyway. I see Samsung has released their "840 EVO" and Sandisk their "Ultra plus"; both price competitive units though I know nothing about what to expect when it comes to reliability or life expectancy. Suggestions?
  2. Intell macrumors P6


    Jan 24, 2010
    Aluminum iMacs rarely overheat. They have a very well designed cooling system and have a very high amount of passive cooling via their body. In that model iMac, you can put any SATA drive without needing to short out any pins. They detect the hard drive temperature by sensing the drive's body with a thermistor on a wire. When installing the SSD, simply put the HDD thermistor onto something that will get warm, not hot, but warm. For a long life SSD that would max out that iMac's SATA II bus, get either a Samsung 840/840EVO/840Pro or the Sandisk Ultra Plus.
  3. toddzrx macrumors 6502a


    Nov 20, 2012
    Most SSD kits come with a 2.5" to 3.5" adapter/bracket; my Corsair SSD did, and that was 3 years ago. I did have to drill a hole in it to get a mounting screw to work, but other than that it has worked fine. You can also just Velcro the thing in there.

    I installed HDD Fan Control on my 2010 iMac. Yeah, paid $30, but it works fine.

    Also, keep in mind that even though your older Mac is running SATA II speeds, you might consider getting an SSD with a SATA III connector. That, and the 250GB-class SSDs are generally faster than their smaller brothers (i.e., 128GB and below).

    Not trying to school you; sounds like you might already know this if you've installed them in a Pro. :eek:
  4. macstatic, Oct 16, 2013
    Last edited: Oct 16, 2013

    macstatic thread starter macrumors 6502a

    Oct 21, 2005
    I have no problem getting schooled -always something new to learn :)

    So older iMacs (like this 2008 model) use external thermistors attached to the outer body of the hard drive (with tape?) while newer iMacs simply connect to an internal thermistor which is only present in "Apple" designed hard drives and not "generic" hard drives or SSDs?

    Intell: why should I place the thermistor on something warm as opposed to specifically on to the new SSD? After all, isn't the whole point to monitor the drive? And there are at least two other thermistors inside the iMac as well, right? So if the motherboard, CPU or the internal area in general overheats the fan(s) should kick in to cool it all down again, correct?
  5. Intell macrumors P6


    Jan 24, 2010
    You'd want to place it on something warm because the SSD won't get hot enough for the system to register the sensor. When that happens it'll go into fail safe mode and make all three fans run at full speed to protect itself.
  6. grandM macrumors 6502a


    Oct 14, 2013
    noob question

    I'd like some advice. Apple 's quite expensive in my country. Here are apple additional prices (in euro):
    7200-rpm seriële ATA schijf van 1 TB
    7200-rpm seriële ATA schijf van 3 TB [+ 150,00 €]
    Fusion Drive van 1 TB [+ 200,00 €]
    Fusion Drive van 3 TB [+ 350,00 €]
    256 GB flashopslag [+ 200,00 €]
    512 GB flashopslag [+ 500,00 €]
    1 TB flashopslag [+ 1.000,00 €]

    It made me wonder if it weren't better to buy an ssd drive of samsung, throw out the 7200 drive and connect an external hdd ( LACIE Externe harde schijf Porsche Design P'9230 - 4 TB USB 3.0 ).

    I just saw that the SAMSUNG Interne SSD 840 Series Basic 2.5" - 500 GB (MZ-7TD500BW) costs 361 euro, SAMSUNG 840 EVO MZ-7TE500 - Solid state drive - 500 GB - intern - 2.5" 303 euro, the SAMSUNG Interne SSD 840 Pro Series Basic 2.5" - 512 GB (MZ-7PD512BW) 410 euro, the SAMSUNG 840 EVO MZ-7TE1T0 - Solid state drive - 1 TB - intern - 2.5" 538 euro. All those are Sata. Or is this a stupid idea? Please your advice :)

    1. would 256 ssd suffice combined with external HDD ( LACIE Externe harde schijf Porsche Design P'9230 - 4 TB USB 3.0 )?
    • would it be easier in a mac mini than imac?
  7. macstatic, Oct 17, 2013
    Last edited: Oct 17, 2013

    macstatic thread starter macrumors 6502a

    Oct 21, 2005
    I see. Yes, that makes sense. The system probably assumes that a thermistor is malfunctioning when it goes below a certain temperature (which is too low for an assumed hard drive).

    So, with the HDD thermistor mounted on something warm, will this particular iMac (with its 3 thermistors and 3 fans) adjust fan speeds automatically as it always has?
    In other words: there's no need for my wife to get geeky, install fan controlling software, keep track of the temperature all the time and manually increase the fan speed whenever she notices that the temperature is getting too high?
    She just wants to get things done and not think about the computer.
  8. Intell macrumors P6


    Jan 24, 2010
  9. laxen2 macrumors newbie

    Oct 18, 2013
    Good thread! These tips will come in handy when I'll upgrade my imac sometime next month. I've watched a few youtube tutorials and it seams manageable.
    That velcro thing for the 2.5 inch disk was... brilliant, would never had thought of that :)

    How do you guys like the performance after the switch to SSD?

    I'll upgrade my 2008 2.66 imac anyway but just wanted to hear what you think. Was it worth it?
    I know my way around electronics but hey, I am about to open up a non malfunctioning imac, just to make it faster... Plus the spending of 120€ on an SSD drive.
  10. macstatic thread starter macrumors 6502a

    Oct 21, 2005
    While awaiting the tools to arrive I've been watching upgrade videos and one in particular mentioned that the SATA cables inside the iMac are really short and with a 2.5" to 3.5" adapter sled it simply won't reach.

    Are there any specific adapter sleds which work better than others in relation to position and direction to the SATA/power cables?

    Also, where inside the iMac is a suitable warm place to attach (with tape I presume) the HDD thermistor?
  11. Mike Oxard macrumors 6502a

    Mike Oxard

    Oct 22, 2009
    I just fitted a Samsung 840 in my 2008 imac. Following the iFixit guide made it very easy. I didn't use an adapter, the SSD is just held in place with sellotape and the heat sensor is taped to the SSD. it has been working fine for about a month :) An added bonus was cleaning the screen, it was much dirtier than I'd realised, so now it runs AND looks like a new computer, the display is noticably brighter.
  12. SlCKB0Y macrumors 68040


    Feb 25, 2012
    Sydney, Australia

    They mimic the size and shape of a 3.5" drive and have the power and SATA connectors in the correct location.

    I prefer the AdaptaDrive.
  13. macstatic thread starter macrumors 6502a

    Oct 21, 2005
    Excellent advice! I've ordered a Newertech AdaptaDrive as you suggested and already received the suction cups so I'm almost set.
  14. Brian33 macrumors 6502a

    Apr 30, 2008
    USA (Virginia)
    I've done this for my 8,1 Early 2008 24" iMac, and the operation was a success.

    I just transferred the HDD's external temp sensor to the new SSD. My Plextor SSD came with an adapter, but it wouldn't work (dont' remember exactly why), so I ended up using thin foam double-sided tape to just stick it in place!

    My fan works normally as far as I can tell, usu. at 1200 rpm according to iStat Menus.

    As a bonus, I replaced the optical drive with a 1 TB HDD and created my own do-it-yourself Fusion Drive. Works great! If you do this, note that the optical bay does not have SATA interface -- it's ATA (aka PATA) -- and you need the right adapter.

    Good luck with your project! It will turn out really nice with that SSD in there.
  15. Brian33 macrumors 6502a

    Apr 30, 2008
    USA (Virginia)
    I love my 24" iMac even more, now! I'm very happy with the improvement, but haven't made any real attempt to measure it. This machine is my daily-user machine. I could use my much faster MacBook Pro with SSD, but I rarely use it at home. The iMac SSD operation fixed the annoyance I used to feel if I had to log in "fresh": finder windows were slow updating and apps took too long to launch the first time. Copying files is, of course, fantastic now.

    Since I replaced the optical drive with a 1 TB 2.5" HDD, I'm in love with Fusion Drive, too, and recommend it to anyone who has an interest and the extra $ to spend.
  16. Jambalaya macrumors 6502a

    Jun 21, 2013
    Keep us posted - it's great to hear how these things go from start to finish
  17. macstatic thread starter macrumors 6502a

    Oct 21, 2005
    I will, when I get the time to finally install it all :)
  18. SohoCC macrumors newbie

    Nov 16, 2014
    sense-check on upgrade plan

    Hello all, very new here, looking for advise on my imac 8.1. 24'' SSD upgrade plan. I realize this thread is older now, but its the only one specific to my model and plans, so I hope the post is welcome!

    I have read most SSD upgrade guides by now, guess I'm a little late to it - waited for SDD's to become a bit cheaper. I now have a Crucial 512GB MX100 SATA 6Gb/s 2.5" bought - I hope I bought a suitable one!

    The spec of my imac; 8.1, 24'' on OS X 10.8.5 (12F45) (3.06 GHZ, 4 GB/800)

    I have hesitated upgrading to Maverick and now Yosemite for fear the spec of the system wasn't suitable, as its running well still atm, but getting slow.

    The Question!

    Most people replace their existing HD with a 2.5'' drive which they place in the former optical bay on PATA with a extra HD adapter (which I bought already) and they place the SSD instead of the 3.5'' HD.

    My plan is to buy some SATA extension cables and cross over the PATA to SATA adapter to the 3.5 bay and from the SATA connector to the optical drive extra HD tray. I would use SATA extension cables to do this.
    The 24'' machine has quite lot of space inside so crossing over with the cables should be fine.

    The reason, 1/ don't need to buy and extra 2.5 drive, 2/ and here-in lies my question to you - can boot the machine up from PATA??? and run the commands for Fusion drive, which will then start moving most used data to he SSD.

    That's my theory anyway, but I have not found anyone describe it, so maybe not a good idea?

    I have seen several video's of people booting their system from a secondary HD and converting to Fusion set-up keeping their original OS, and avoiding the need to re-install or restore from timemachine. (I do have a dedicated Timemachine drive on Firewire btw).

    Much welcome your insights or direction to other threads I may have not picked up.
  19. Brian33 macrumors 6502a

    Apr 30, 2008
    USA (Virginia)
    Very interesting idea! So, if I understand you correctly, the optical drive PATA interface will be connected to a PATA-to-SATA adapter connected to a SATA extension cable to a 3.5" HDD in the original HDD bay. And the SATA connector in the original HDD bay will connect to an extension cable to a 2.5" SSD mounted in the original optical drive bay. It that right? Or, were you planning upon connecting a SATA extension cable to the motherboard (instead of in the SATA HDD bay itself) and route that to the optical bay?

    It's a neat idea that would let you use a 3.5" hard drive! As far as I know it might work, but I'm NOT an expert, that's for sure. My concern would center around room for the ends of the extension cables in each of those bays.

    What PATA to SATA adapter did you get? The one I used (at would not have room to plug in the extension cable leading to the HDD bay and still have space for the SSD to fit into it.

    Likewise, while I can't quite remember the layout of the original SATA HDD bay, I would guess that there's no space to plug in the extension cable that goes to the optical bay plus the extension cable from the optical bay plus the actual 3.5" drive. You'd better look at a bunch of photos first or open up your machine first!

    As far as "booting from PATA:" I don't think that will be a problem. You're going to create a DIY Fusion drive with the SATA SSD and the PATA HDD, right? That's what I've done. Creating the Fusion drive creates a single Logical Volume out of the two that OS X is certainly able to boot from (after installation).

    (I just realized you probably meant booting up the first time after your hardware changes? Well, for that you need to make a bootable USB flash/thumb drive with the OS X installer on it. Make this FIRST and test its bootability before you make any hardware changes! Hope this makes sense.)

    This part I didn't really understand. Anytime you create a Fusion drive you "wipe out" the contents of its component drives and must re-format (and re-install or restore, if it is to be your boot drive).

    Have you seen this thread? Not sure if it's useful but certainly relevant:

    I've got an Early 2008 iMac 8,1 24" on OS X 10.8.5 (2.8 GHz, 6 GB RAM), so I have almost the exact same machine as you have. I've successfully done the DIY Fusion drive (but using a 2.5" HDD in the optical bay) and the result has been simply wonderful. Hope you figure out something that works!

  20. SohoCC macrumors newbie

    Nov 16, 2014
    Hi Brian, yes you got the concept spot on!
    Thanks for your insights!! I didn't do my reading right, cause you are absolutely correct - Fusion set-up wipes drives, so I will need to reinstall OSX and return to current state via Timemachine.

    I have only seen images of the 24'' 8.1 iMac open, I haven't yet opened mine. I will order 2 sets of sata extension leads, angled connector and straight, see what works - but take your point, it might not fit, in which case I will use a 2.5 drive which is a former back-up, samsung spinpoint 7200 500GB, which I can break out of the case, but if I can avoid it, I will.

    I ordered a similar product, and it comes apart easily and the PATA to SATA convertor is an inch by 1/4 inch L-shaped component board, small enough/flat enough to fit somewhere I hope. The bracket is thin aluminum, so I can cut away some to fit the sata connector for the 2.5'' SDD. I will document the process and figure out how to post it somewhere, if need be stitch the images for a youtube clip.

    I have to familiarize myself a bit more with Timemachine, was hoping to avoid it, but you have shown me Fusion will wipe my HD. Thanks Brian, I'll post how I got on

    Brian (also as coincidence will have it ;) )
  21. Brian33 macrumors 6502a

    Apr 30, 2008
    USA (Virginia)
    Good idea -- it sounds like this could work for the optical bay, then. That leaves the 3.5" HDD bay...

    Please do post whether it works or not -- I'm quite curious. Who knows, maybe I'll get the urge to put a 4 GB (or larger!) 3.5" HDD into mine using your method!
  22. al85 macrumors member

    Aug 31, 2006
    How did the install go. Im looking to do the same.
  23. macstatic thread starter macrumors 6502a

    Oct 21, 2005
    Sorry, just haven't gotten round to it yet. Still using the hard drive.

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