I'm trying to do CPU mining as part of a pool that I found here -- https://xmrpool.net/#/help/getting_started . As I have crappy hardware, I thought I'd try the easiest setting. The site says difficulty 1000 if you connect to port 3333 of one of their servers. So this is what I did, and then I started getting jobs. However, I noticed the target for those jobs seems greater than 1000, for example


Even though this "target" value is in hex, when unraveled, the value is greater than 1000 (the above is decimal value 4294967 if I'm reading it correctly). What am I missing here? Or is the pool sending things of much harder difficulty than what is advertised?

1 Answer 1


The port used defines the starting difficulty.

From the pool doc you referenced:

The Port is used in conjunciton with the url and is used to specify the starting difficulty.

As soon as you submit a result, the pool updates your difficulty for the next job it sends you based on how long it took you to hash the last (or to be more accurate, it averages your previously submitted job/hash times and adjusts based on block time). This is to ensure the server sends you jobs with a difficulty that can be expected to be hashed within the block time window and not overload the server sending lots of small difficulty jobs to miners that can be expected to hash higher difficulty per job.

Most pools allow you to specify a fixed difficulty. With your pool, if you wanted a fixed difficulty of 3500, this is done by appending +3500 to your wallet address (username). Example (again from the doc you referenced):

Username : 43To46Y9AxNFkY5rsMQaLwbRNaxLZVvc4LJZt7Cx9Dt23frL6aut2uC3PsMiwGY5C5fKLSn6sWyoxRQTK1dhdBpKAX8bsUW+3500
  • Thanks for this explanation. So if I have never mined any shares from the pool and I specify a target difficulty of 3500, should the first job come back at or near 3500 difficulty? I ask because with the particular pool I mentioned the first job had a target difficulty of "7db91200", which I'm reading as 1227133 difficulty, despite my "3500" specification.
    – Dave
    Commented Jun 7, 2018 at 20:18
  • Firstly did you specify a fixed diff in the username? Secondly, it will never be a 1-1 mapping because the pool adjusts based on block target time. You can review the code yourself here. Most of the difficulty updating is from there onwards.
    – jtgrassie
    Commented Jun 8, 2018 at 10:51

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