I often see QUIC described as "faster than TCP", but in my experience this has only been the case when it comes to handshake latency. Throughput-wise, I've fou

I often see QUIC described as "faster than TCP", but in my experience this has only been the case when it comes to handshake latency. Throughput-wise, I've found in real-world testing that QUIC is often slower than TCP: (1) QUIC uses more CPU, due to the processing in user-space. 1Gbps required 3 CPU cores. On my 1x-CPU VPS, QUIC maxed out at 400Mbps due to the CPU. With TCP+TLS, I could comfortably achieve 5Gbps. (2) QUIC was less resilient to packet loss (surprisingly). This was particularly noticeable on mobile devices. If your use-case is to move bytes between powerful servers over a reliable, wired connection, QUIC may beat TCP in most ways that matter. But for use in real-world mobile apps, TCP may still offer better throughput. Caveat: This is all data from using the quic-go package. The C libraries may well be more efficient :)