Ele diz no artigo:
Many people think that flash disks do not benefit from defragmentation and optimization because bandwidth and access time are the same for the entire disk, unlike mechanical harddisks which are faster at the beginning than the end. But fragmented files need extra processing time inside Windows, not noticeable on mechanical harddisks but very significant on fast flash memory disks. Even more important is free space optimization. Flash memory is written in large blocks, and if free space is fragmented then Windows has to (read and) write much more data than the size of the file. This takes time, which translates into lower speed.
Portanto, se você tiver um arquivo composto de 4 pequenos blocos de dados de, digamos, 1k cada, cada um em um bloco de leitura / gravação diferente (digamos, uma página) de, digamos, 128k de tamanho, 4 páginas devem ser transferidas (totalizando 512k) apenas para obter os 4k de dados.