std.hash.Crc32 is byte-at-a-time over one table (~350 MB/s here) and the open-time scan CRCs every payload byte, so it was ~93% of a cold open. Slicing-by-8 in its place: a 416 MB store opens in 292ms against 1.22s, warm reads run 3.3x, the write path 1.5x. Bit-identical by construction, so no format changes and no repository is affected. check-in: 602c2459f2 user: dmestas tags: trunk