What you're seeing is the effect of file system caching buffers running out on the operating system (used for write caching, caching of indices, caching of the transaction log file etc.) and the PC having to go to disk.
We had this exact same issue with regards to our stock price databases. All looks rosy until your database hits a few hundred MB. The solutions (in rough order of importance): Use prepared queries, don't index fields you don't have to, optimise your database as much as possible to reduce the bytes used for each field, add more RAM, get quicker disks (eg. Command queuing such as some SATA and pretty much all SCSI drives), increased RPMs and more on-board cache. Best regards, Richard Dale. Norgate Investor Services - Premium quality Stock, Futures and Foreign Exchange Data for markets in Australia, Asia, Canada, Europe, UK & USA - www.premiumdata.net
