TaPaKaH from HW-DB has another review done! This time around he had a look at the HyperX Savage HX428C14SBK2/16 kit and overclocked it to DDR4-3000C13 at 1.37V. Below a quote:

"Speaking of the spec clearance, we have registered 0.08V of headroom on our sample. That is, running DDR4-2800 with CL14 has required our kit just 1.27V with a Kingston's rating of 1.35V. On top of that, the timings could be lowered from 14-15-15-39 to 14-14-14-28 without any additional voltage increase. Typically for 8GB modules based on Hynix 4Gbit MFR, a fully stable operation at DDR4-3200 or higher clockspeeds was out of reach. At the end of the day, the best result we got out of our Savage was 1500MHz CL13 with 1.37V. This result is very impressive in its own right, however, there was a major issue that has spoiled our experience."

Full review at HW-DB.com