Hi, I had exactly the same problem. I Googled around and a lots of people facing exactly the same problem. It seems that this problem occures to AM3/775/Older boards with PCIE 1.0 slots. Mostly boards with a basic chipset causes this problem
My setup was:
AMD Phenom II X4 965
ASUS M4A87TD EVO
6 GB DDR
120 GB SSD
1 TB SATA
Corsair 1000 Watt HX1000i
R9 290 4gb
I had an AMD 7950 card which worked perfect, no bsods no BCCODE 124 at all. I swapped my ddr, swapped my gpu for my old one, swapped even my cpu. ofcourse new BIOS updates aren't available for new hardware anymore.
Newest drivers for all of my hardware were installed, it was totally up 2 date.
Standard questions for a BCCODE 124 are:
Vcore problems, Overclocking, faulty cpu, faulty ddr, it could be anything.
Now I found out the problem.
When I played games it constantly freezes and restarts, blackscreens, even youtube was too much.
I found out that these motherboards aren't able to give the requested power to the GPU through PCIE, which causes data loss. So on that point when a higher amount of power through PCIE is required, your system freezes and restarts cause of a voltage error.
You can't do anything about it. All lowbudget, non gaming boards on AM3 or LGA 775 (maybe more) will not support a card which really needs a PCIE 3.0 slot like the R9 290.
I bought a new setup to test this for you guys.
Specs:
Intel i5 4690K
Gigabyte GA-Z78X-OC
Corsair Vengeance 8GB
(my old R9 290)
Corsair HX1000i
And the rest of the disks and stuff where no one cares about.
I installed everything, start gaming for 4 hours nonstop. no problems, no high temperatures.
Conclusion:
A better motherboard with supported features does the trick.
