Slow access on Oracle Tablespaces is typically caused by multiple processes accessing the same set of data at the same time. This is often related to the time of day or date, so there is not always a way to work around this issue. You may be seeing one or more tablespaces periodically showing access times > 10ms. The slow access is not always on the same datafile in the tablespace, or even in the same tablespace.
Considerations Review the RAID configuration used for the datafiles in these tablespaces. Move the tablespaces to drives with less activity. Make sure they do not share drives with other high activity tablespace. Cache as many tables as possible from these tablespaces. If the slow access continues, consider the select use of Solid State Storage by placing one or more of these tablespaces on solid state drivers.