I'm on RS1 332, first time run on Antutu I received a score of 89k, second time I received 83k, noticed the phone was also warmer so I put my phone in the freezer for about 20 minutes and ran it again, score went up to 96k so it's highly likely that hot phones are getting throttled. My 1520 does getter hotter than the 950XL but the 950XL seems to warm up faster. My 1520 is on the same build and first scored 61k, then 60k then in the freezer for 20 minutes and then scored 62k. I bet the 950XL has a lot more throttling going on than the 1520, which is why it doesn't get hotter than my 1520, but still even when throttled, it performs the test better.