Another remedy is reformatting MyDocs with smaller allocation blocks. But please keep in mind two things: 1. The smallest allocation block you can achieve on such a large partition is 8KB. Better than the default 64KB that's for sure, but given that the average tile size is about 4KB, you still waste about 50%. 2. Smaller allocation block means there is more of them. Which means that the FAT is bigger and more RAM is used by the file system cache, leaving less RAM available for applications. Unless you intend to share the tiles with other applications, your best option is using the sqlite database as Whispering Weasel suggested.