Hashcat slows down after staring attack.
I'm having the same problem, only I am cracking ethereum wallet with SCRYPT algorithm.

I'm doing this on AWS, it seems that the hash rate slows down slowly over the course of the day, until I'm down to 1 h/s (from 12 h/s using 8 CPUs).

Is it possible that AWS is reducing performance? Here is my command:

./hashcat64.bin -m 15700 -a 0 -w 3 -D1 --force --scrypt-tmto=1 /home/ubuntu/crackme.txt /home/ubuntu/words.txt --status --status-timer=30

OpenCL info:

Platform ID #1
  Vendor  : Intel(R) Corporation
  Name    : Intel(R) OpenCL
  Version : OpenCL 1.2 

  Device ID #1
    Type           : CPU
    Vendor ID      : 8
    Vendor         : Intel(R) Corporation
    Name           : Intel(R) Xeon(R) CPU E5-2676 v3 @ 2.40GHz
    Version        : OpenCL 1.2 (Build 475)
    Processor(s)   : 8
    Clock          : 2400
    Memory         : 8043/32174 MB allocatable
    OpenCL Version : OpenCL C 1.2 
    Driver Version :

Thank you so much!!
This is totally not the same problem. As you have read from the original post the user was using 779 networks instead of 1. In your case it's probably heating. Keep a look at the temperature. If it goes up to high, the drivers will downclock the GPU (which you will see as well). Also try with -w1 and -w2.