hashcat performance dropped after a day of using.

[fhd]

hello guys , the speed was around 1500 MH/s ~ 2000MH/s and now dropped to 400MH/s . with the same command, my OS is windows 10 , i haven't done any changes.

i tried -w 3 and the performance still the same.

[fhd]

Session..........: hashcat
Status...........: Running
Hash.Type........: sha1($salt.$pass)
Hash.Target......: C:\hashcat-4.1.0\1.txt
Time.Started.....: Sat Jun 30 23:49:49 2018 (3 mins, 45 secs)
Time.Estimated...: Sat Jun 30 23:55:10 2018 (1 min, 36 secs)
Guess.Mask.......: *****?d?d?d?d?d?d?d?d?d?d [15]
Guess.Charset....: -1 ?d, -2 Undefined, -3 Undefined, -4 Undefined
Guess.Queue......: 1/1 (100.00%)
Speed.Dev.#3.....:   407.2 MH/s (1.14ms) @ Accel:128 Loops:1 Thr:1024 Vec:1
Recovered........: 12/25 (48.00%) Digests, 12/25 (48.00%) Salts
Progress.........: 174439792640/250000000000 (69.78%)
Rejected.........: 0/174439792640 (0.00%)
Restore.Point....: 6976962560/10000000000 (69.77%)
Candidates.#3....: *****1855375485 -> ****7506874836
HWMon.Dev.#3.....: Temp: 60c Util: 77% Core:1873MHz Mem:3802MHz Bus:16

[s]tatus [p]ause [b]ypass [c]heckpoint [q]uit =>

[fhd]

Benchmark :
Hashmode: 120 - sha1($salt.$pass)

Speed.Dev.#3.....:  3321.3 MH/s (49.70ms) @ Accel:128 Loops:128 Thr:1024 Vec:1

[atom]

If you have a static prefix in your mask, the speed is low. If you have multiple salts at the same time the effect with static prefix is mitigated until they get cracked (as in your case). Then the bottleneck kicks back in.