i don't think that's an unfair comparison, that is in line with similar tests i have performed for random write workloads on lsm trees and b trees that don't fit in ram, including cost of compaction. https://youtu.be/jwq_0mPNnN8?t=3730 links to a section of a talk i did which explains my benchmarks. it also includes some pretty neat visualizations of the write patterns of the two data structures that may help people understand why there is such a big difference in write throughput. my benchmarks were done on spinning disk, on ssds i'd expect lsm trees to only have around 10x higher write throughput for the same benchmark.