First off do you have the latest Bios and chipset driver and GPU driver installed? If not do that.
Make sure you have your bios at defaults for stability testing. You can change it from there to enable PBO and or XMP later once you are stable.
If that does not help:
Most the time when you get freezes the Memory is the place to start looking. First off make sure you have the memory sticks in the correct slots for a 2 stick configuration. The motherboard should be able to tell you. Likely if you are building your system you know to look for this but worth mentioning.
Next test one stick at a time. Try each stick by itself and see if that makes a difference if so you are done because a stick is bad.
If that doesn't help, I would put both back in and run OCCT from OCBASE dot COM. See if it finds issue with your GPU, PSU or other components.
If all checks out there. Then I would contact Gigabyte Support as they should be able to help isolate what issue they think you have and you can go from there. They should be able to give good help since most the components are theirs and your memory is on the QVL list.
Good Luck!