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.<p>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.<p>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.<p>Caveat: This is all data from using the quic-go package. The C libraries may well be more efficient :)