Why does Kaspa's block validation become harder as block rate increases?

When Kaspa's block rate increases by a factor of R, the difficulty adjustment algorithm becomes R² times more complex — not just R times. The difficulty adjustment algorithm (DAA) must maintain, for each block, a list of past blocks with the highest accumulated weight and traverse that list to compute the correct mining difficulty target. Speeding up the block rate means each individual block requires R times more processing steps, and blocks also arrive R times faster, so the two effects multiply together. The current Golang implementation uses specific window sizes — 263 blocks for timestamp flexibility and 2641 blocks for the DAA window — to manage this overhead. This matters because it explains why simply increasing block speed in a proof-of-work system is not free: it directly increases the computational load on every node validating the chain.