Crosshair VIII Hero x870e post code 99

[Nordjaevel]

Recently I decided up upgrade to the current generation AM5 socket; I'm currently experiencing post code 99 (Super IO initialization). This is what I have tried so far to remedy the problem:

• RMA for a new motherboard 
• Boot with one stick of RAM
• Swapping RAM
• Resetting the CPU
• Changing to the current generation PCIe riser cable 
• Resetting the CMOS various times 
• Flashing the latest BIOS
• Changing the GPU to the horizontal position so that it is connected directly to the motherboard 
• Removing the sound card 
• Unplugging and plugging the mouse and keyboard 
• Using a different keyboard 

Nothing has worked to get to the BIOS for a first time setup. I'm at a loss. Is there anything else that I can do? Why is it not booting into the BIOS?

Specs:

• Ryzen 9950x
• Crosshair VIII Hero x870e 
• 32 (2x16) Trident Z DDR5 7200
• Sapphire Toxic 6900 XT
• Sound Blaster X AE-5 (not connected)
• ASUS ROG Loki 1,000 watt PSU ATX 3 

[Nate152]

Hello Nordjaevel

In my experience, if you have display with code 99, it's usually some usb device.

If you have no display with code 99, it's usually something with the gpu, monitor cable, or monitor.

I see the Saphire Toxic 6900XT has two 8-pin and one 6-pin pcie power connectors. The ROG Loki 1000w has two standard pcie power cables for a total of three connectors. I imagine you're using both cables and have the three connectors populated. But, you should really be using three separate pcie power cables, this could possibly be the issue.