The most reliable and efficient udp packet size?

Question

Would sending lots a small packets by UDP take more resources (cpu, compression by zlib, etc...). I read here that sending one big packet of ~65kBYTEs by UDP would probably

Answer 1

534 bytes. That is required to be transmitted without fragmentation. It can still be lost altogether of course. The overheads due to retransmission of lost packets and the network overheads themselves are several orders of magnitude more significant than any CPU cost.