Disk Cache

The disk cache is used to keep frequently accessed data in memory to reduce the number of reads and writes to the hard drive. BitTorrent Mainline normally manages the cache automatically, but you may change its behavior by modifying these settings. Because of the nature of the settings, caution should be exercised when modifying the settings, as bad settings may be detrimental to performance.

Disk Cache

• Override automatic cache size and specify the size manually allows you to set a new maximum memory usage for the disk cache. Normally, BitTorrent Mainline automatically adjusts the cache size based on your current download speed. This value is interpreted in MiB, so please enter it as such. Any value below 1 will be ignored, and 1 will be used instead.
• Reduce memory usage when cache is not needed flushes unused parts of the disk cache when BitTorrent Mainline is not transferring data.

Advanced Cache Settings

• Enable caching of disk writes allows BitTorrent Mainline to use the disk cache to store data in memory before writing it to disk. This option has the effect of decreasing the frequency of writes to disk.
  
  • Write out untouched blocks every 2 minutes makes BitTorrent Mainline write to disk the 16 KiB blocks of data in memory that haven't been touched for 2 minutes or longer and don't fill up a piece. This option has the effect of decreasing BitTorrent Mainline's memory usage while increasing the frequency of writes to disk.
  • Write out finished pieces immediately makes BitTorrent Mainline write a piece to disk once it is completed in memory. This option has the effect of decreasing BitTorrent Mainline's memory usage while increasing the frequency of writes to disk.
• Enable caching of disk reads allows BitTorrent Mainline to use the disk cache to store frequently read data into memory from disk. This option has the effect of decreasing the frequency of reads from disk.
  
  • Turn off caching if the upload speed is slow disables the read caching if uploading is below 40 KiB/s. This option has the effect of decreasing BitTorrent Mainline's memory usage while increasing the frequency of reads from disk.
  • Remove old blocks from the cache removes chunks of read cache data from memory if they haven't been accessed for 10 minutes in order to make room for other data. This option has the effect of decreasing BitTorrent Mainline's memory usage while increasing the frequency of reads from disk.
  • Increase automatic cache size when cache thrashing increases the disk cache size when reading from disk increases (most often due to increased upload speeds). If you override the automatic cache size, this option is not needed.
• Disable Windows Caching of disk writes disables Windows' native caching of writes to disk. This option helps when the Windows disk cache sometimes causes an extremely large amount of physical system memory to seemingly "disappear" while BitTorrent Mainline is downloading quickly (because it is trying to cache BitTorrent Mainline's increased disk writing rate). When memory becomes fully used, page swapping occurs, which can cause slowdowns. On the other hand, enabling this option may cause increased disk seeks, which may decrease transfer rates when the BitTorrent Mainline disk cache is full.
• Disable Windows Caching of disk reads disables Windows' native caching of reads from disk. This option helps when the Windows disk cache sometimes causes an extremely large amount of physical system memory to seemingly "disappear" while BitTorrent Mainline is uploading quickly (because it is trying to cache BitTorrent Mainline's increased disk reading rate). When memory becomes fully used, page swapping occurs, which can cause slowdowns. On the other hand, enabling this option may cause increased disk seeks, which may decrease transfer rates when the BitTorrent Mainline disk cache is full.