Hi, I really had the same problem one week ago. I really thought my mainboard had a defect. But when I looked at BIOS, I noticed that the Memory Timings (CL-RCD-RP-RAS) were setted wrong. So I set them to "auto" and applyed the values.

After that I never had a freeze again. I hope this may help you, but a freeze can usually happen when you are using a onboard soundcard + external soundcard at the same time.