New Q9550 CPU causing otherwise stable system to freeze/hang

I recently bought a new Q9550 to finish upgrading my home built PC, and can't get it to run correctly. I've spent days browsing forums, and trying several recommendations with no success.

I've tried removing all but 1 stick of Ram and 1 GPU (trying all four RAM sticks with each GPU), but the results are always the same. It will usually allow me to load Windows (Vista Ultimate 32-bit), but after maybe 10 - 15 minutes it freezes, all the fans stay on though.

My specs are below, and the PC runs fine when I put my old Dual core (6400 @2.13 Ghz) back in:

ASUS P5N-D 750i SLI
Intel Core2Quad Q9550 2.83 Ghz CPU
GeForce 8800 GTS
PNY 8800 GT
4x1GB OCZ DDR2 PC2 8500 SLI-enabled RAM
Coolmax RM 750W PSU
Seagate 500 GB HD
LG DVD Burner (not sure exact model)
Coolermaster (Centurion?) case
17 answers Last reply
More about q9550 causing stable system freeze hang
  1. You might need a bios update for the 750i, I know when 750i came out they didnt play nice with any quads over q6600.

    Set the ram specs manually in the bios, they might be under volted by default.


    Since it works with old CPU you need a bios update almost for sure.
  2. If you need to update the bios, put the old processor in first, then update the bios.
    Did you set the memory voltage?
    Run memtest86+ and check for erros.
  3. I should've mentioned this in my first post, but I did update to the latest bios (1101) shortly after putting the new CPU in. I read where people using a different Asus board were able to overcome similar problems by reverting to an older bios, but haven't tried that yet.
    I did try it after setting the voltage and CAS latency to the factory specs (5-5-5-15 @2.1 volts)
    Memtest wouldn't complete, as the system would freeze after about 5 - 10 minutes after loading no matter what I tried to do.
  4. Sory if that wasn't clear, after I tried updating the bios, and puting in the memory settings manualy I was getting the same problem.
  5. I just ran memtest86 (using my old dual core) with no issues. At least I don't think there were.
    I burned the ISO image, and booted from the CD. It ran a test, but before I could see what it was doing started booting into windows. Is this what was supposed to happen?
  6. No. It should stay in memtest86+.
  7. I see now, I was using memtest86, not memtest86+. I just finished running the + version and passed with no errors.
    I'm thinking that I'll need to RMA the CPU, but I'm definitely open to any suggestions.
  8. Hi, i dont think its your cpu. did you try adjusting the voltage in bios? for cpu? ram? fsb? Sometimes it is possible for the memory to act weird
  9. I have the voltage for my ram, and CPU set. I wasn't planning on overclocking, so I didn't go far over the minimum specs though.
    2.11 volts on memory
    1.3 volts on the CPU
    Couldn't find the specs for how I should set my fsb, and didn't really want to mess with that withoput knowing.
  10. Having the same problem with same CPU and MOBO... System runs perfect with my old E8500. Current BIOS. Any help is appreciated. I'm not attempting any OCing, everything set to default.
  11. Thank you very much for the suggestions everyone (and to saro58 for validating this issue). I've been doing a lot of reading through forums, and elsewhere, and have been learning alot, but no matter what I do in the BIOS I'm still having this issue.

    I've tried different memory ratios for my FSB, I've even underclocked my CPU, but haven't found any solution, the system even freezes in my BIOS lately.

    Right now, these are the main settings I have setup:

    Voltage control:
    Vcore: 1.25
    DRAM: 2.21 (tried 2.11 for awhile too)
    HT: Auto
    NB: Auto
    SB: Auto

    FSB&Memory configuration
    Clock mode: Linked
    Ratio: 5:4 (tried 1:1, 3:2, maybe others too)
    FSB(QDR) 1333
    Actual QDR 1333
    Actual Mem 1066.7 (with other ratios tried at 800 too)

    CPU confuguration
    Auto Thermal Control: Auto
    Limit CPUID MaxVal: Disabled
    Enhanced C1: Enabled
    CPU C State Capability: Disabled
    Execute Disable bit: Enabled
    Virtualization Technology: Enabled
    CPU Multiplier: 8 (tried 8.5 first, but thought underclocking could work)
    Enhanced Intel SpeedStep Tech: Disabled

    Other settings (was in a hurry to get to work and can't remember where these were found off the top of my head)
    LDT Freq.: 4x (was at 5x by defazult but I thought that might be high)
    All Spread Spectrum function disabled
    Mem Timing: 5-5-5-15-2T - those are factory specs, but I tried 4-4-4-12 after seeing it recopmmended on another post, still no love :( - It's back on factory specs now
    Advanced Mem timing all on Auto

    I'm really at a complete loss here, and will greatly appreciate any help I can get. I hear the P5N-D can be pretty picky, and am worried it might need to be replaced.
  12. hudson said:


    ASUS P5N-D 750i SLI
    Intel Core2Quad Q9550 2.83 Ghz CPU
    GeForce 8800 GTS
    PNY 8800 GT

    4x1GB OCZ DDR2 PC2 8500 SLI-enabled RAM
    Coolmax RM 750W PSU
    Seagate 500 GB HD
    LG DVD Burner (not sure exact model)
    Coolermaster (Centurion?) case

    Typo?
  13. Sort of... I meant to delete the PNY 8800 GT from this thread but forgot.

    I did buy the 8800GTS months after buying the 8800 GT (mistakenly), but with my old dual core I did have them running together with the SLI bridge (maybe not correctly though- was told that it probably dumbed down the GTS so that it could run with the GT) - there weren't any issues when I ran them together on the dual core.

    Nonetheless, I never did try them both with the quad core, I'm only using the 8800 GTS at the moment.
  14. Thanks for clearing that up.
  15. Not a problem... thanks for checking!
  16. i have the same problem with my q9550 on my 750i sli ftw. i can tell you it is not the cpu because i exchanged my cpu and still had this problem. rite now im RMA'ing my motherboard and see if that fixes anything.
  17. XvCluTchvX said:
    i have the same problem with my q9550 on my 750i sli ftw. i can tell you it is not the cpu because i exchanged my cpu and still had this problem. rite now im RMA'ing my motherboard and see if that fixes anything.



    After more testing and reading, my conclusion was that the problem was with my mobo too, or just the 750i in general. Where the mobo was over a year old, and I couldn't afford a new one, I just returned the CPU for a refund (minus the 15% restocking fee).
    I'm just gonna give it some time, save some cash, and then start building my dream machine!
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