I'd run something like Memtest86+ for a few passes or overnight if you've manually specified the speed, timings and voltage for those sticks. 1333 CL9 isn't outlandish by any means and the majority of kits should be able to support that. If you get any errors in Memtest it might be indicative of failing RAM which you could RMA for a replacement.
Okay thank you, I'm gonna try that right now.