Here are the specs on the MSI MS-7641 760M-P23 (FX) mother board.
https://us.msi.com/Motherboard/760GM-P23-FX/SpecificationThe PCI eX slot is a Gen2 and his 1080 is a Gen3, Gen2 will support a Gen3 card. I ended up getting a new motherboard that supported Gen3 and DDR3 RAM with a quad core I5. His CPU has the grunt, he hasn't posted what his power supply is rated or a DXdaig. If it comes down to it, the cost of a new motherboard that will accept his cpu and ram along with a Gen3 slot will be less than the 1080 itself.
999 your power supply rating and a DXdiag would help your audience. In the simplest case, what's happening could be a weak power supply, in the worst, swapping out the video card has exposed an issue with the motherboard getting old which happens all the time with PC's. And why I had to upgrade.
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• 64bit AMD® FX, Phenom II X6/X4/X3/X2, Athlon II X4/X3/X2 and Sempron CPU.
Please refer to CPU Support for compatible CPU; the above description is for reference only.
Hyper Transport Bus
• HyperTransport 3.0 supporting speed up to 5200MT/s
Chipset
• AMD® 760G and SB710 Chipset
Main Memory
• Supports two unbuffered DIMM of 1.5 Volt DDR3 800/1066/1333 DRAM, 16GB Max
Slots
• 1 PCI Express x16 slot with x16 operation (PCI Express Bus SPEC V2.0 compliant)
• 1 PCI EXpress x1 slot
• 1 PCI slot, support 3.3V/ 5V PCI bus Interface.
On-Board SATA
• 6 SATA 3Gb/s (1~6) ports by AMD® SB710
- Supports storage and data transfers at up to 3Gb/s
RAID Function
- SATA 1~6 support RAID 0, 1, 10 or JBOD mode by AMD® SB710