Hard disk does not provide zero latency or infinite bandwidth. uTorrent might be complaining “100% Disk IO” all the time and refuses to download or upload for quite a long time. Even without this case - the following settings achieve a higher disk endurance (less writes).

Run μtorrent with Administrator.

In “Advance”

• Double the value of diskio.cache_stripe from default value

• • • you might try tripling or quadrupling too if your data bandwidth is over 20MB/s

• Double the default value of diskio.coalesce_write_size

• • • if you tripled/quadrupled diskio.cache_stripe then x3/x4 to diskio.coalesce_write_size as well to maintain scheme

• Enable diskio.no_zero, diskio.smart_hash and diskio.sparse_files.

In “Advaned – Disk Cache”

• Override automatic cache size and specify the size manually. Something like 256MB or 512MB works well (default 64-128).

• • • The larger the better for downloads and uploads - but leave some margin for other programs. If uTorrent uses too much RAM -> test with a lower value. Remove override if you want uTorrent to manage itself - it does it poorly.

• Enable caching of disk writes, do NOT write out untouched blocks every 2 minutes but DO write out finished pieces immediately.

• Enable caching of disk reads, do NOT turn off read caching if the upload speed is slow, do NOT remove old blocks form the cache but DO increase automatic cache size when cache thrashing.

• Do NOT reduce memory usage when the cache is not needed.

In “General”

Do NOT pre-allocate all files - otherwise diskio^ settings above wont function.

MORE:

“100% Disk IO” means uTorrent is running out of write caches. Above settings almost are just trying to ensure write cache does not run out.

diskio.cache_stripe is the size of blocks of memory used in it’s disk cache in KiB. Default value is somewhat too small to avoid unnecessary disk IO.

The option diskio.coalesce_write_size tells uTorrent to try to minimize the number of writes to disk by writing more data at once. Default value equals 2MB - with that uTorrent is constantly hammering disk, so double, triple or quadruple.

Enabling diskio.no_zero causes uTorrent to skip the zero-filling process for file allocation. It only tells the file system to reserve the space but do not actually issue disk access. Helpful if you are downloading very large torrents.

The option diskio.smart_hash makes uTorrent hash data from memory (if in the write queue) instead of flushing to disk, re-reading from disk, and then hashing - reduces disk access.

The option diskio.sparse_files enables diskio.no_zero magic.

EVEN MORE:

In “Advaned – Disk Cache”

uTorrent claims to manage cache size automatically but it only uses a fixed 64-128MB cache. Increasing the value significantly reduces disk access.

Caches are helpful. But memory space is limited and if you do not write out immediately, uTorrent will occasionally keep it in memory for good and once write cache runs out ~ uTorrent stops functioning.

In “General”

Do NOT pre-allocate all files so that diskio.no_zero and diskio.sparse_files would work.