Getting black screen while running Prime95 stress test

So this is very confusing to me, I initially set me voltage to 1.45 and multiplier to 22 and ran Prime 95 for a few minutes before exiting it. Then I raised the multiplier to 23 and the second I clicked run on Prime95 my screen went black and I had to turn off the computer my manually switching the power supply.

Then I lowered the multiplier to 22 and kept the v-core at 1.475; instant black screen. Tried running Prime95 at 1.45v and 22 multiplier and it ran for 12 mins before giving me the black screen and forcing me to manually switch off the power supply.

I played with the voltage a bit more (up and down) and am getting the same result. Now I am insanely confused. Thanks in advance.

Specs are:
AMD FX-8350
Gigabyte 990FXA-UD3 Rev.4
This memory (4 sticks) http://www.newegg.com/Product/Product.aspx?Item=N82E16820231460
Corsair H80i water cooling
This Power Supply: http://www.newegg.com/Product/Product.aspx?Item=N82E16817139104
2 Sli EVGA 2GB GTX 760's
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More about black screen running prime95 stress test
  1. Hi and welcome to Tom's forum.

    I would say (pretty sure) that your problem is for not enough voltage on the CPU, but let's play a little more around this.

    What temps are you getting? What settings do you have in BIOS? What is the max frequency that you can hit stable without change voltage?
  2. Ok, I got a little more info for you. I tried playing with it for a few hours this morning and here's what I got:

    I set v-core to 1.4175 which was what it said it was running on Auto in bios.

    Following features disabled: CPU Unlock, Turbo mode, C1E, C6, APM, Cool n Quiet.

    I then was able to get 4.2ghz per core stable on the 4.175v.

    Then I bumped it to 4.4 and got it stable at around 4.375v.

    I proceeded to increase the multiplier to get 4.6ghz and got it stables around 1.49v.

    Temps never went above 47c for any tests (mostly around 44 until I put voltage to 1.49v.

    Now, here's what I found out, when I initially started overclocking yesterday I set LLC to extreme. I forgot to do that this morning, after I had a stable 4.6 @ 1.49v I flipped LLC to extreme and boom black screen and my peripherals turn off (mouse, KB).

    I hope this helps. Also The HT is set to factory auto at 2200 and NB also on auto at 2600. I hear lowering the NB can give a better OC but I'm a bit new here.
  3. Set LLC to auto and check in CPUZ your voltage as well as in CoreTemp. What is the differente with those two and the BIOS voltage?

    Regarding the HT and NB, NB gives you better performance with high frequency RAM while HT above 2000MHz doesn't really help.
  4. saint19 said:
    Set LLC to auto and check in CPUZ your voltage as well as in CoreTemp. What is the differente with those two and the BIOS voltage?

    Regarding the HT and NB, NB gives you better performance with high frequency RAM while HT above 2000MHz doesn't really help.




    Interesting CPU-V core was reading at 1.416v and Dram at 1.488. LLC is set to auto. With my RAM would you recommend keeping BB at 2600 or dropping it down?
  5. What voltage you had on BIOS when you take that screenshot?
  6. saint19 said:
    What voltage you had on BIOS when you take that screenshot?


    I had it set to 1.49v, this was also taken 3 mins into a stress test on Prime95.
  7. So, your vDropp is around 0.074V. Not much to worry about, try to use an LLC configuration not extreme and check again if the black screen come back again.
  8. saint19 said:
    So, your vDropp is around 0.074V. Not much to worry about, try to use an LLC configuration not extreme and check again if the black screen come back again.


    Ok, the BIOS has some odd LLC settings: There is Auto, Normal, Low, Medium, Extreme, and Standard

    At Normal and Standard I netted the same 1.416, at Medium I was ranging between 1.476-1.488.

    I read somewhere that people bump up the NB core to 1.3v when running LLC but I'm not sure if that related.
  9. What happen with stability?
  10. saint19 said:
    What happen with stability?


    It was stable for 13 mins at Medium.
  11. Any ideas?
  12. But it's totally stable on auto right?
  13. saint19 said:
    But it's totally stable on auto right?


    Yes
  14. I would leave it on "Auto", if it's stable and with good temps and settings.
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