Motherboard model: P8P67 PRO Rev 1.01
UEFI Version: 3207
CPU: i5-2500k
Memory kit part number (s) and amount in GB: Micron MT8JTF51264AZ-1G6E1 4GB
GPU: GTX 980 , GTX 1060 3GB, AMD Radeon HD 6450
SSD/HDDs/Optical drives: 240GB Sandisk SSD
PSU: EVGA 600w bronze
USB Devices (model/version number):MODGUO HP Mouse and DBPOWER K928 Keyboard
Monitor: Acer P244w
CPU Cooler: DEEPCOOL GAMMAXX 300
PC CASE: CoolerMaster HAF EVO
Operating system: Microsoft Windows 10 Professional x64 - Microsoft Activated yes/no? yes
Drivers Installed (include version): Unknown, I've used various versions and I think it doesn't matter.
Any third Party temp/voltage software installed: No
System Overclocked (provide details)? No
Issue:
The system will not POST with only a single GTX 980 or a single GTX 1060 3GB. The VGA LED remains solid red when only a single only of these GPUs are present. These GPUs have both been tested and are fully functional in another system working alone. These GPUs will also work perfectly fine in this system as long as they are both installed at the same time, regardless of which is in what slot. The system will POST fine with a single amd gpu. I've tried different memory, different memory slots. The memory has also been tested extensively and works fine in another system (and in this one when it completes POST)
The system completes POST and works perfectly when:
- Both the GTX 980 and GTX 1060 3GB are installed, regardless of which one is in what slot.
- Either the (GTX 980 or GTX 1060 3GB) and AMD Radeon HD 6450 are installed.
- The AMD Radeon HD 6450 is installed alone.
What I've tried:
- Clearing CMOS
- Removing battery for over 24 hours with AC disconnected from the PSU. (somehow it seemed to remember the BIOS settings?)
- Updating BIOS to latest version
- Rolling back BIOS to an older version
- Removing the motherboard and all components from the case, testing with only CPU, single memory stick, and single GPU on an insulated motherboard box. (with all usb devices disconnected, only monitor plugged in to see if i could get a POST screen)
I'm stumped. The computer works fine with a nice GTX card as long as I put in a cheap radeon to go with it, but I really don't want to have that extra card in there and it's been begging me for quite some time. I've used this computer daily for over a year with the radeon card installed alongside the GTX card and I've finally decided I want to see if I can solve this very weird problem.
