i recently built a sandy bridge system using these 2 sets of 8gb gskill memory - F3-12800CL9D-8GBRL and F3-12800CL9D-8GBXL. bios says they are running at the rated 1600 via XMP profile 1 but CPU-Z and AIDA64 both say one set is running at 1600 and one set at 1333. XMP shows as enabled and dual channel in CPU-Z. I am currently stress testing with prime95 and have had zero errors for over an hour so far. has anybody ever experienced this? system specs are in signature. thanx