# Performance is really slow with high CPU usage!

**URL:** https://forum.duplicati.com/t/performance-is-really-slow-with-high-cpu-usage/1113
**Category:** Support
**Created:** [October 22, 2017, 1:37pm UTC](https://forum.duplicati.com/t/performance-is-really-slow-with-high-cpu-usage/1113 "2017-10-22T13:37:53Z")
**Posts on this page:** 1
**Showing post:** 16

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### Author: ![kenkendk](https://forum.duplicati.com/user_avatar/forum.duplicati.com/kenkendk/32/5305_2.png) [@kenkendk](https://forum.duplicati.com/u/kenkendk)
#### Post date: [October 30, 2017, 4:12pm UTC](https://forum.duplicati.com/t/performance-is-really-slow-with-high-cpu-usage/1113/16 "2017-10-30T16:12:43Z")

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> [@Wardrop](#):
>
> Changing the hash algorithm from SHA256 to MD5 gave a ~15%. improvement. Combining them nearly got us to 50% overall improvement. Still not quick enough to flood my gigabit connection, certainly not on my lower spec server.

Apart from the parallel hashing, there is another speedup in the canary that uses the (terribly named) NgHash. But you can also get it to use the OpenSSL hashing library, which is faster in my tests. You need to drop in the version of the OpenSSL library you are using from here: [FasterHashing/Windows-DLLs at master · kenkendk/FasterHashing · GitHub](https://github.com/kenkendk/FasterHashing/tree/master/Windows-DLLs)

Then set the environment variable `FH_LIBRARY=openssl` and it should load OpenSSL and use that for hashing.

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