I just built myself a new PC based on the Gigabyte GA-990FXA-UD7 and AMD FX-9590 chip.
Before I could even think about overclocking, I started getting total system freeze issues.
After a lot of troubleshooting, I found that I can avoid the freeze issues by disabling all the C-State options in the BIOS.
After I found this out I had a chat with Gigabyte Tech Support and was told that basically the AMD CPU is not performing the C-State changes to specification. This would suggest all FX-9590 chips will have this issue.
Just wanted to get this out there in case anybody else has a similar issue.