Resolved Mac Pro not booting after CPU Upgrade

Discussion in 'Mac Pro' started by Okta, Apr 4, 2018.

  1. Okta, Apr 4, 2018
    Last edited: Apr 6, 2018

    Okta macrumors newbie

    Joined:
    Apr 20, 2014
    #1
    Hey everyone,

    You guys have been such a great help in the past I figured I'd ask for your assistance once more!

    I tried to install two X5660s into a Mac Pro 2009 flashed to 5,1. One CPU works just fine but the moment I try to screw in CPU B the system just boots forever. Eventually a red light turns up and nothing happens.

    I've tried 3 different CPUs, two of which I can guarantee work.

    I didn't add washers but I added thermal pads to the bottom sensor array

    Any ideas?

    EDIT: More Details.

    The red light that stays on is OVTMP CPUB. I'm going to check tomorrow for bent pins, if I can't find anything I'm going to give up and go back to the old pocessors.

    EDIT: Success! I delidded the processors by using the Vise Method (then I shaved off as much of the solder as I could with a razor, thermal pasted, used the little shells that came with the old CPU, installed it) and it worked. Thank you everyone here!
     
  2. chscag macrumors 68030

    chscag

    Joined:
    Feb 17, 2008
    Location:
    Fort Worth, Texas
    #2
    I wonder if you're over stressing the power supply which may be weak with that second CPU? Do you have a spare PS you can try?
     
  3. Okta thread starter macrumors newbie

    Joined:
    Apr 20, 2014
    #3
    Hmm interesting. I have an EVGA PSU lying around. Do standard power supplies work?
    --- Post Merged, Apr 4, 2018 ---
    EDIT: Just checked and it won't. I may try to use it to power the GPU and offload that from the computer. That'll free up 150W+ from the system.
    --- Post Merged, Apr 4, 2018 ---
    PSU GPU override didn't help. I did notice that sometimes the red CPUB fail light turns on
     
  4. minifridge1138 macrumors 65816

    Joined:
    Jun 26, 2010
    #4
    Just to recap:

    Dual processor MP 4,1 --> 5,1

    Are the processors lidless?
    Are you using washers?
    Did you clip the fan wiring harness?


    You put a processor in CPU A. You leave CPU B empty.
    What happens?
    Does it boot? Does it see all of the RAM? Does the fan run like crazy?

    You put a 2nd processor into CPU B.
    What happens?
    Does it boot? Does it see all of the ram? Does it see both processors? What are the fans doing?

    2 X5660s should not stress the PSU so much that it refuses to boot (last week I put 2 X5680s into a MP 4,1).
     
  5. h9826790 macrumors G4

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #5
    From memory, OVTMP red light is one of the common error when the heatsink screw tension is not right.

    Sure you should check the socket before you do anything further.
     
  6. Okta thread starter macrumors newbie

    Joined:
    Apr 20, 2014
    #6
    They aren't delidded. I didn't use washers. I made sure the fan connection is in. It boots, sees 4 slots and goes into Jet engine mode if I remove processor B. When I put the second in and turn them in 3.5 times it boots just fine but doesn't recognize the second processor and all the ram. Though the fans don't go crazy. I put a half a turn more and it boots forever.

    I checked the socket and it looks perfect. I re-installed a working CPU and made sure to count my turns *exactly* to 3.5. Now it boots but only shows one CPU. Any tighter and it doesn't boot. The fans don't go full speed which makes me think it's working but not being recognized? If I take the processor completely out the fans go jet engine on me. Its operating like a normal mac otherwise.
     
  7. bsbeamer macrumors 68000

    Joined:
    Sep 19, 2012
    #7
    Probably will not make any difference, but have you tried removing some RAM? Two matching sticks per each CPU.
    After that, does system report two or four sticks of RAM?
     
  8. Okta thread starter macrumors newbie

    Joined:
    Apr 20, 2014
    #8
    Yup, I tried that. Down to two 8GB OWC sticks. It only recognizes 4 slots until I screw the other CPU in a bit more in which case it doesn't boot at all
     
  9. h9826790 macrumors G4

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #9
    So, up to this moment, if you put the original CPU back in, the cMP can still work normally?
     
  10. Okta thread starter macrumors newbie

    Joined:
    Apr 20, 2014
    #10
    I'm trying that now. This computer is unbelievably frustrating.
     
  11. robbier macrumors member

    Joined:
    Apr 27, 2008
    #11
    Check for overtemp damage to the socket - I recently was upgrading a 2009 4,1 with lidded CPUs and screwed one heatsink in just slightly too tight. Got an overtemp indicator and noticed that some of the socket pins were melted and there were burn marks on the bottom of the CPU. These machines are extremely sensitive to heatsink screw tension if you are using lidded CPUs - too loose and the machine won't boot, too tight and you can destroy the socket and CPU when turning the machine on. My current strategy that seems to work every time I upgrade a 4,1 with lidded CPUs is to screw in each heatsink screw just until I feel a bit of tension, and then turn it a quarter turn more.
     
  12. minifridge1138 macrumors 65816

    Joined:
    Jun 26, 2010
    #12
    Without washers, it is easy to overtighten things. I highly recommend getting some (a pack of 5 was $0.48 at my hardware store). A stack of 3 was a height of 2.35mm. The height difference between lidded and non-lidded CPUS was 2.25.

    I had no luck counting turns on mine. I tightened until there was tension. Then booted to see if it worked and then tightened things 1/8 of a turn more until everything worked.

    iStat Pro was also very helpful because it showed me which CPU fan wasn't running, which told me which CPU I needed to tighten when the system booted but something wasn't recognized.
     
  13. Squuiid macrumors 65816

    Squuiid

    Joined:
    Oct 31, 2006
    #13
    Just do this properly and delid the CPUs before you cause any permanent damage to your sockets.
    But a cheap vice from Amazon and pop the lids off by tightening the vice. Search this forum for specifics.

    Washer method can work but is prone to costly mistakes. Not delidding nor using washers is madness!
     
  14. Okta thread starter macrumors newbie

    Joined:
    Apr 20, 2014
    #14
    I put the originals back in and it works fine. I'll see if I can use the vice method. Just need to acquire a vice haha
     
  15. Okta thread starter macrumors newbie

    Joined:
    Apr 20, 2014
    #15
    You my friend are awesome. Used the Vice Method, Shaved off as much of the solder as I could, thermal pasted the delidded CPUs in, tightened it up and now I'm typing to you on a Mac pro with dual X5660's and 128GB of RAM.

    Thank you sir!
     

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