> (Also, curiously when the data's in the cache that page shows a performance penalty for async reads that complete synchronously from the cache compared to syn

> (Also, curiously when the data's in the cache that page shows a performance penalty for async reads that complete synchronously from the cache compared to sync reads. Wonder why.) Because a synchronous operation is always faster than an overlapped operation if it can be completed synchronously. Lots of stuff happens behind the scenes when an overlapped operation occurs.