Is Boot Camp killing my video cards?

Discussion in 'iMac' started by NoNig, May 5, 2014.

  1. NoNig macrumors newbie

    Mar 2, 2014
    Hi everybody

    I'm seeking response to a rather strange problem.

    Around January (2014) I bought a used 2011 21.5 iMac (2400S, HD6750M) and soon installed a Samsung 840 EVO 120 GB SSD and additional 16 Gigs of RAM for a total of 20 Gigs (pre-installed 4 Gigs).

    Everything was doing just fine, until one morning when the iMac wouldn't boot. I took it to an Apple-certified repair/reseller (Eplehuset). They took a look at it and said that I had to change the logic board.

    After some thought, I bought a new logic board on eBay along with a new video card module (it too was a HD6750M). I installed the parts, and everything was running just fine until recently, when it wouldn't boot - again.

    Some of the circumstances are similar/the same:
    - I'd just been running Mac OS X (DIY Fusion Drive; SSD + 250 Gigs of HDD) and had selected the Windows partition (the remaining 250 Gigs of the HDD) for start disk.
    - The computer chimes
    - The panel lights up (i can se the lights turn on)
    - Image remains black

    In both cases, I've tried all the SMC, PRAM/NVRAM, etc. - no dice.

    However, this time around, I can see some heat markings on the logic board itself. It wasn't like that, the last time.

    I've attached some images, so you can compare for yourself:




    These two shots, are images of the old logic board.


    It did occur to me, however, that my installation of the SSD might have changed/obstructed the internal airflow. As you'd might now, the heatsink for the video card is in the top of the case.

    What bothers me is, that I've been gaming for hours (in Mac OS X [Portal 2, CoD4:MW] and Windows [SupCom:FA and other games]) without any problems.

    I switch between Windows and Mac OS X on a daily basis, so please don't consider this as being Windows-bashing. It's just my observation, that both times, I came right from Mac OS X, chose Boot Camp as start disk, hit reboot, and bam! Dead iMac.

    Any thoughts?

    EDIT: Oh. Forgot to mention, that in both cases, the diagnostics LED's on the logic board, shows no sign of trouble (all four lights up just fine).
  2. NoNig thread starter macrumors newbie

    Mar 2, 2014
  3. cypriot, May 26, 2014
    Last edited: May 26, 2014

    cypriot macrumors regular

    Oct 14, 2011
    Is Boot Camp killing my video cards?

    Its hard to tell but my fan seems to kick way more often when i start windows. That means it heats more. It could mean a defective fan though.
  4. rambo47 macrumors 6502a


    Oct 3, 2010
    Denville, NJ
    Boot Camp and a different OS **shouldn't** put that much extra stress on a graphics card. A high-end video editing app might, but not BC/Windows.

    I suspect the SSD install you mentioned could be the culprit. The iMac is a tough design for cooling. Any all-in-one enclosure is going to present problems with cooling so changing the internal airflow pattern in any way could be the cause.
  5. omvs macrumors 6502

    May 15, 2011
    Have you tried hooking up an external monitor? You might have to do it with the internal panel disconnected to get a boot image - not sure offhand.

    I would think you'd be okay with your setup - looks like you're mounting the SSD under the optical drive? You might consider moving the ODD temp sensor to the SSD - it probably runs hotter than the optical drive. I used a optical drive -> 2.5" adapter on my 27" to put a second drive in that slot, and stuck the sensor right on the drive.

    I also assume you've reseated the LCD cable? On mine its a pain in the *ss to get in right - I've broken the pins on the cable side (thankfully easy to replace) and more recently hadn't seated it right and after a day it pulled out just enough to disconnect the LCD prox sensor, though the datalink still worked.

    I wouldn't be surprised if the windows games were beating up the GPU more than the mac ones. I think I get better frame rates under Windows for the same games, and Tomb Raider under windows on my machine will crash unless I override the fans to kick on a earlier (used Mac Fan Control to slave ODD fan off GPU temp). Haven't managed to crash OSX yet.
  6. NoNig thread starter macrumors newbie

    Mar 2, 2014
    That's strange. My observation is the direct opposite - meaning; I've noticed, that the fans doesn't occur to be spinning up when I'm in Windows. Unfortunately, I haven't been able to get a proper temperature reading [When in Windows] because every program I've tried reports temperatures between 2,700,000 ºC and -500,00 ºC (I know. It's the last one that makes me think it's not working properly :roll eyes: ).

    That's sort of the same conclusion that I ended up with. It bothers me though. First of all, then it would appear it's all my own damn (stupid stupid stupid) fault - that I can understand. But what I can't understand is, why then, didn't I observe any problems (for instance instability, shutdowns, etc.) when gaming for longer sessions and periods of time?

    The SSD has been there, from day one, so to speak. Could it perhaps be, that the fans shut down when rebooting, and in that short period of time, there is too much heat generation going on - which then kills my video card? If that's the case, why didn't it die one of the numerous times I've made an ordinary [Mac OS X to Mac OS X] reboot :confused:

    I see your point, but somehow fail to agree with you ;) :p

    That I have, and no luck. I bought a mDP -> HDMI connecter, that I hooked up to our television. Didn't produce an image. Just for safe measure I tried the connecter on another computer and it [the connector] worked just fine.

    That I did, yes.
    I could try that. That would indeed give some indication (if any?) whether or not heat is building up, around the or due to the SSD. Didn't think of that myself - great idea :)

    Affirmative. I've checked the cable (in fact, all of them) very carefully each time. They appear to be in fine order.

    I honestly couldn't tell you, based on sure fact, due to the reason mentioned earlier (my poor experience in trial and error, regarding temperature reading software), whether or not the GPU is running hotter.

    My very unscientific research (based on the well known: "reach back, over the vent in the top, and make a subjective temperature reading judging by the hot air"-method) tells me, that the GPU isn't heating up [the air] in a significant way.

    However. If the airflow, somehow, have been obstructed, that isn't a particularly good thing.

    After the holiday - and all my exams (I'm graduating as teacher this summer), I think I'll make one last effort to make this thing work properly.

    My 'bucket list' for the computer is:
    - rearrange the cables, and SSD-position/mounting, to optimize airflow
    - buy a new video card
    - buy a new logic board

    However. If it turns out, that I'm unable to save the computer, only by buying a new video card (since I already have two logic boards laying around) I think I'm calling it a "learning experience" - sell the spare parts [that work, obviously] and buy myself a new "27 iMac (perhaps one from the rumored fall refresh) :)
  7. NoNig thread starter macrumors newbie

    Mar 2, 2014

    Well. I recieved the new video card today - a HD6750M - and the computer still refuses to boot properly.

    This bugs me beyond belief, since I actually like the computer and wanted to see it serving its purpose for some years.

    I guess I'll stick to my previous plan, and call quits on this project.

    My assumption now, is, that it's the logic boards that have failed and not (necessarily) the video cards.

    Dang it!
  8. insane79 macrumors 6502

    Aug 20, 2008
    I have read elsewhere that on bootcamp the fans in the iMac kick in very late on windows then on mac osx, there are threads regarding this if you do abit of googli. Could be it contributed to the problem.
  9. Georgio macrumors 6502


    Apr 30, 2008
    Essex, UK
    The 2012/2013 iMac refresh really sorted out the over-heating problems; I had a 27" 2011 model and you could fry eggs on the top bezel after a few hours use.
    In the end I fixed redundant processor heatsinks along the bezel and rigged up an external 6" fan to draw hot air out of the top of the case. Not good.

    Roll on to May 2013 and I pick up a new 27" iMac and I'm amazed how cool it runs even when the ambient temperature is hot.
    The only time I hear the fan(s) is in Bootcamp and even then after an evening heavy gaming the Mac is barely warm.
  10. NoNig thread starter macrumors newbie

    Mar 2, 2014
    That seems very plausible. Especially during a longer period of time with repeating cool-down and heating going on.

    I have to admit, I kinda lost my love to the 2011 iMac - based on my experience with the particular unit I ended up buying. My only 'problem' now is, do I:

    a) Save up money for a new (late 2013 or possible 2014) model and try to sell the parts for/of the 2011-one I have now?

    b) Make one last attempt on saving this particular unit ($ ~500 USD for a new logic board), and end up spending as much (actually a little bit more) as if I'd bought a new one back in January?
  11. Dirtyharry50 macrumors 68000


    May 17, 2012
    I would not recommend spending another penny on a mid-2011 27" iMac based on my own experience with heat issues that ultimately led to Apple replacing my iMac with a brand new late-2013 under AppleCare.

    My iMac was serviced in my home three times and a fourth call was needed before they opted to give me a new one. The problem was heat in each case. They replaced all three fans, the Superdrive, the LCD panel twice (damaged by heat), the glass panel twice (damaged by heat), the GPU (6970m damaged by heat) and at the time of the final service call it was going to need, the LCD was damaged again and the hard disk was failing.

    True story.

    What I took away from that? My mid-2011 was a lemon from a model year with known issues with heat, Apple is excellent about standing behind their products, always buy AppleCare.

    My new late-2013 27" iMac is wonderful. It runs nice and cool all the time. I too enjoy gaming on my Mac and have had no problems with this one. That said, I will still be buying AppleCare for it which Apple is graciously allowing me to do so that I can have a full three years warranty on the replacement computer. They refunded a prorated balance on the AppleCare for the failed computer that needed to be returned.

    I'm sorry you've had such a bad experience but I think you'll find the new iMacs to be much better and you'll be gaining a better GPU, etc. for gaming too with a new one. Just be sure to get AppleCare to save you in case of problems. For me, it was so worth it.
  12. NoNig thread starter macrumors newbie

    Mar 2, 2014
    That's it then. I'll try to sell the parts and save up for a new iMac.

    When it ran, it was a wonderful machine. Still is. In a way, it's a pretty desktop ornament... a $ ~1,500 USD non-functioning desktop ornament.
  13. Georgio macrumors 6502


    Apr 30, 2008
    Essex, UK
    Sorry to hear of your experiences, but if you can get either try and pick up a late 2012 i.e. the latest generation of iMacs, or hold out for the refresh which could be just round the corner with hopefully a new generation of GPU's.

    I think after all the heat issues with the 2011 model, they must have bought in specialists to sort out the new model (2012+) as it runs so cool it's like night and day.
  14. Dirtyharry50 macrumors 68000


    May 17, 2012
    I loved mine too when it wasn't melting itself. The new one is even better and does not have that problem. :D
  15. insane79 macrumors 6502

    Aug 20, 2008
    Yes the new slim iMacs run super cool, do you game via bootcamp on your 2013 iMac? if yes does it seem to get hotter when in windoze?

  16. dollystereo macrumors 6502a


    Oct 6, 2004

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