Wouldn't surprise me - G.skill does have quality issues.
Go to
Memtest86+ - Advanced Memory Diagnostic Tool and download Memtest86+. Download the auto installer for USB key and use it to make a bootable USB key, boot with it and run it overnight. It will run till you stop it, if there are errors it will be obvious.
If you don't have a spare blank USB key or you can't get it to work, download the iso and use that to make a bootable CD.