X299 Extreme 4 No POST with multiple CPUs

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   Hello.
  I'm hoping someone could point me in the right direction please.
  Two brand new boards with the same issue, so I must be missing something or have something wrong.

  X299 Extreme 4, Box label says: Part No 90-MXB690-A0UAYAZ  X299 EXTREME4/A/ASRK.
  BIOS label says P2.00.
  new Intel Core i9-9820X 10-Core 3.3 GHz LGA 2066 165W CD8067304126901 Desktop Processor.
  (1)new Kingston 4GB 2666 MHz/PC4-21300 CL19 unbuffered - Non-ECC in DDR4/SlotA1.
  new Musetex MU1000 power supply - 24 pin harness to ATXPWR1 port, 8 pin harness to ATX12V1 port(also tried V2 port).
  used, known good Nvidia Quadro K600 video card.
  new UP1 cooler fan to PWM_CFG1 CPU_FAN1 port.

  Board is not mounted in the case, I have it on plastic stand-offs on my table.

  When I turn on the power supply, the board LEDs under the heat sink will light solid green, then change to a slow blue flash.
  When I jump pins PWRBTN# and GND on the 9-pin PANEL1 header, the cooler fan spins up, the LEDs continue the slow blue flash for 3 or 4 seconds, then the cooler fan and fan in the power supply stop briefly, then the power supply and cooler fan restart. Slow blue flash, reset loop. I get no beeps, and no POST video.

  I have tried two brand new boards(thinking the first was DOA), a spare known good i9-7900X CPU, a known good Corsair 1000W power supply, 8 sticks of known good Samsung 16GB 2Rx8 PC4-2666V-UB1-11 RAM in different combinations of slot positions and numbers. I have also tried a brand new Radeon RX580 video card. 

  Everything I have brings me to the slow blue flash reset loop.

  Strangely enough, the actual board layout isn't the same as the drawing in the manual.

  Thoughts or suggestions on what I have wrong please?

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Random_Poster Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 13 May 2026 Location: USA Status: Offline Points: 15	Post Options Post Reply Quote Random_Poster Report Post Thanks(0) Quote Reply Topic: X299 Extreme 4 No POST with multiple CPUs Posted: 3 hours 41 minutes ago at 8:36pm
	Hello. I'm hoping someone could point me in the right direction please. Two brand new boards with the same issue, so I must be missing something or have something wrong. X299 Extreme 4, Box label says: Part No 90-MXB690-A0UAYAZ X299 EXTREME4/A/ASRK. BIOS label says P2.00. new Intel Core i9-9820X 10-Core 3.3 GHz LGA 2066 165W CD8067304126901 Desktop Processor. (1)new Kingston 4GB 2666 MHz/PC4-21300 CL19 unbuffered - Non-ECC in DDR4/SlotA1. new Musetex MU1000 power supply - 24 pin harness to ATXPWR1 port, 8 pin harness to ATX12V1 port(also tried V2 port). used, known good Nvidia Quadro K600 video card. new UP1 cooler fan to PWM_CFG1 CPU_FAN1 port. Board is not mounted in the case, I have it on plastic stand-offs on my table. When I turn on the power supply, the board LEDs under the heat sink will light solid green, then change to a slow blue flash. When I jump pins PWRBTN# and GND on the 9-pin PANEL1 header, the cooler fan spins up, the LEDs continue the slow blue flash for 3 or 4 seconds, then the cooler fan and fan in the power supply stop briefly, then the power supply and cooler fan restart. Slow blue flash, reset loop. I get no beeps, and no POST video. I have tried two brand new boards(thinking the first was DOA), a spare known good i9-7900X CPU, a known good Corsair 1000W power supply, 8 sticks of known good Samsung 16GB 2Rx8 PC4-2666V-UB1-11 RAM in different combinations of slot positions and numbers. I have also tried a brand new Radeon RX580 video card. Everything I have brings me to the slow blue flash reset loop. Strangely enough, the actual board layout isn't the same as the drawing in the manual. Thoughts or suggestions on what I have wrong please?

Xaltar Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Joined: 16 May 2015 Location: Europe Status: Offline Points: 38078	Post Options Post Reply Quote Xaltar Report Post Thanks(0) Quote Reply Posted: 2 hours 44 minutes ago at 9:33pm
	I have never owned an X299 system but I can make some suggestions based on my experience with other HEDT systems. 1. Single stick of RAM in slot A2 2. Make sure the CPU is properly seated in the socket and that you don't have too much mounting pressure on your cooler, that can cause pads to lift off pins in the socket. 3. Leave the system powered on for at least 10 mins, the first RAM training on HEDT systems (quad channel capable) can often take longer than you would expect. If none of that works then double check to make sure your clear CMOS jumper isn't set in the "clear" position and make sure you have the correct cables connected for CPU power, you only need a single cable connected to POST so I typically do this when troubleshooting then add the second one once the system is up and running. Good luck and let me know how it goes.