Please post your full specs, including make/model of your PSU (unfortunately PSUs vary in quality dramatically).
What settings and resolution are you playing at?
Common causes for freezing are heat &/or power related - a bottleneck can (rarely) present the same symptoms.
The most likely:
1. How do your CPU/GPU temps look? For AMD CPUs, use AMD Overdrive:
http://www.amd.com/en-us/innovations/software-technologies/technologies-gaming/over-drive Look at your 'thermal margin' while gaming, it works backwards in 'degrees to zero'. 70'C is good (it's 70'C until the max thermal limit) and numbers towards 0'C are bad. You want to see 8 or 9'C+ at full load, such as gaming. Anything lower, and your CPU is thermal throttling to avoid damage.
Other options:
2. While gaming, use HWMonitor (Windows task manager works fine for the CPU) to monitor CPU and GPU's utilization. If either of the components are operating at 100%, you're experiencing a bottleneck which can result in lock-ups. I'd suspect temps first & foremost though.
3. Power issues. This will depend mostly on the make/model (and potentially age) of the PSU in question. While the FX6350 + 750 setup should likely need no more than 250W at load, poor power delivery can cause issues too. I'd suspect you'd see stuttering/choppiness long before a freeze though. Even a fairly poor PSU should still be able to power a 6350 + 750, but there's no guarantees with poor quality units.