Performance of C4 when CPU bound

Back in November 2025, when doing tests of C4 on a loopback address, I observed that C4 achieved lower data rates than Cubic or even BBR. Since “performance under loopback” was not a high priority scenario, I filed that in the long pile of issues to deal with later. Then, in early January 2026, I read a preprint of a paper by Kathrin Elmenhorst and Nils Aschenbruck titled “2BRobust – Overcoming…