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ASUS Sabertooth 990FX R2.0 / PC wont boot / New Build

Hello Fellas,
I'm in need of some expertise on my new build, please.

When I go to power up the PC, it runs for about 15-20 seconds and the CPU LED lights up and the system just turns off. It never gives me any images on the screen at all.

here's the kicker, If I boot the PC with the MemOK! Button next to the ram it loads up the BIOS quickly and fine, it recognizes the CPU, RAM, everything. as soon as I exit the BIOS though and attempt to start it up normal it just turns off on me the same as before.

I'm really lost as I have no idea what can be happening, everything is new. If anyone can please give me some advice or something it would be much appreciated because from what I'm reading Newegg doesn't take returns on this MOBO and everyone on the comment section is saying the ASUS customer service is horrible when it comes to this board. I'm freaking out :(

Here are my system specs
CPU- AMD FX-4300
MOBO- ASUS Sabertooth 990fx R2.0
RAM- Gskill sniper ddr3 1866
GPU- xfx radeon hd 6870
HDD- samsung 500 gb
SSD- samsung 840 evo
PSU- antec 620 watt gamer m series
CASE- corsair 600t

If you need any other information please let me know ill be happy to supply.

Thank you for taking the time to read this.
12 answers Last reply Best Answer
More about asus sabertooth 990fx wont boot build
  1. my cpu light used to be on for some reason but after a bios update it was gone, flash your bios and manually set your ram speed and timings.

    what bios revision are you on? 2104 is the newest revision
  2. 06yfz450ridr said:
    my cpu light used to be on for some reason but after a bios update it was gone, flash your bios and manually set your ram speed and timings.

    what bios revision are you on? 2104 is the newest revision


    I'm not exactly sure what version of BIOS its running at the moment, Its just running the one that it comes with out of the box. Was yours turning off like mine too?
  3. tctank420 said:
    06yfz450ridr said:
    my cpu light used to be on for some reason but after a bios update it was gone, flash your bios and manually set your ram speed and timings.

    what bios revision are you on? 2104 is the newest revision


    I'm not exactly sure what version of BIOS its running at the moment, Its just running the one that it comes with out of the box. Was yours turning off like mine too?


    no mine was not turning off but the light was always lit, go tot he bios and hit advanced, it should be the first tab that says your bios revision, I would say its on an old revision.

    it has to be bios related or something but i cant say why tis truning off unless our heatsink isnt seated right and its heating up and shutting off.

    I do that occasionally since i have my pump on an auxiliary 12v power brick and I sometimes forget its not longer on my psu so it will heat up with my overlcock in seconds and shut off.


    i would first update the bios and default your settings, then manually set your memory settigns and check the heatsink. what are your temp readings in the bios?
  4. 06yfz450ridr said:
    tctank420 said:
    06yfz450ridr said:
    my cpu light used to be on for some reason but after a bios update it was gone, flash your bios and manually set your ram speed and timings.

    what bios revision are you on? 2104 is the newest revision


    I'm not exactly sure what version of BIOS its running at the moment, Its just running the one that it comes with out of the box. Was yours turning off like mine too?


    no mine was not turning off but the light was always lit, go tot he bios and hit advanced, it should be the first tab that says your bios revision, I would say its on an old revision.

    it has to be bios related or something but i cant say why tis truning off unless our heatsink isnt seated right and its heating up and shutting off.

    I do that occasionally since i have my pump on an auxiliary 12v power brick and I sometimes forget its not longer on my psu so it will heat up with my overlcock in seconds and shut off.


    i would first update the bios and default your settings, then manually set your memory settigns and check the heatsink. what are your temp readings in the bios?


    I'll have to check the BIOS version / temps when I get home and ill let you know asap, I'm at work atm. I don't know the exact temps off my head because I did it on Friday but I know the temps were running normal, nothing crazy hot or anything. For now I guess ill download the latest version of BIOS so that I can flash it when I get home.
  5. Did you make sure that you plugged in the 8pin CPU power cable? Lots of people have issues with the same description as yours, and 9/10 times that is the reason (I myself am guilty of the same thing happening once or twice).
  6. Check to make sure the 8 pin CPU power is snug.
  7. Ill check the 8 pin tonight and let you guys know.
  8. Best answer
    Ok figured it out, I feel about like a dummy Z_z!

    Checked the 8 pin connection, was connected right.
    Updated the Bios, still shut down like it was.

    I took out 1 Ram and it booted up so I figured it out, I had both ram slotted next to each other rather then having them color coroneted.

    PCs working now, thanks for the help fellas its much appreciated!
  9. Great job!
  10. Thanks :)
  11. tctank420 said:
    Hello Fellas,
    I'm in need of some expertise on my new build, please.

    When I go to power up the PC, it runs for about 15-20 seconds and the CPU LED lights up and the system just turns off. It never gives me any images on the screen at all.

    here's the kicker, If I boot the PC with the MemOK! Button next to the ram it loads up the BIOS quickly and fine, it recognizes the CPU, RAM, everything. as soon as I exit the BIOS though and attempt to start it up normal it just turns off on me the same as before.

    I'm really lost as I have no idea what can be happening, everything is new. If anyone can please give me some advice or something it would be much appreciated because from what I'm reading Newegg doesn't take returns on this MOBO and everyone on the comment section is saying the ASUS customer service is horrible when it comes to this board. I'm freaking out :(

    Here are my system specs
    CPU- AMD FX-4300
    MOBO- ASUS Sabertooth 990fx R2.0
    RAM- Gskill sniper ddr3 1866
    GPU- xfx radeon hd 6870
    HDD- samsung 500 gb
    SSD- samsung 840 evo
    PSU- antec 620 watt gamer m series
    CASE- corsair 600t

    If you need any other information please let me know ill be happy to supply.

    Thank you for taking the time to read this.
  12. ASUS tech support doesn't even help you, they just keep pushing you for an RMA. BUT THE REAL PROBLEM FOR ALL IS the 3 pin connector for the cpu . That's the culprit, You need to NEVER connect to the cpu power 3 pin female connector to the mobo 3 pin cpu fan male connector . You have to use the 3 pin female connector from the CPU on the 4 pin male connector just to the right of it on the MOBO called the cpu fan optional, it is a 4 pin male, but you use the 3 pin female cpu connector there and the embedded slot that places it in the right direction IS USED leaving 1 pin unused> so spread the word...the 3 pin male connector on the sabertooth FX990 is useless.
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