Show your status output. You're probably trying to crack more than one digest, thus dividing your hashrate.
Quick edit: Or because it's a laptop your overheating and it's causing your GPU to throttle is more or less probably what it is.
[s]tatus [p]ause [r]esume ypass [c]heckpoint [q]uit =>
Session..........: hashcat
Status...........: Quit
Hash.Type........: WPA/WPA2
Hash.Target......: hccapx.hccapx
Time.Started.....: Wed Feb 28 18:36:42 2018 (3 secs)
Time.Estimated...: Wed Feb 28 18:38:14 2018 (1 min, 29 secs)
Guess.Mask.......: ?d?d?d?d?d?d?d?d [8]
Guess.Queue......: 1/1 (100.00%)
Speed.Dev.#4.....: 1091.8 kH/s (320.80ms)
Recovered........: 0/1 (0.00%) Digests, 0/1 (0.00%) Salts
Progress.........: 2457600/100000000 (2.46%)
Rejected.........: 0/2457600 (0.00%)
Restore.Point....: 0/10000000 (0.00%)
Candidates.#4....: 12345678 -> 17656244
HWMon.Dev.#4.....: Temp: 47c Fan: 61% Util:100% Core:2113MHz Mem:4151MHz Bus:16
.
Quick edit: Or because it's a laptop your overheating and it's causing your GPU to throttle is more or less probably what it is.
[s]tatus [p]ause [r]esume ypass [c]heckpoint [q]uit =>
Session..........: hashcat
Status...........: Quit
Hash.Type........: WPA/WPA2
Hash.Target......: hccapx.hccapx
Time.Started.....: Wed Feb 28 18:36:42 2018 (3 secs)
Time.Estimated...: Wed Feb 28 18:38:14 2018 (1 min, 29 secs)
Guess.Mask.......: ?d?d?d?d?d?d?d?d [8]
Guess.Queue......: 1/1 (100.00%)
Speed.Dev.#4.....: 1091.8 kH/s (320.80ms)
Recovered........: 0/1 (0.00%) Digests, 0/1 (0.00%) Salts
Progress.........: 2457600/100000000 (2.46%)
Rejected.........: 0/2457600 (0.00%)
Restore.Point....: 0/10000000 (0.00%)
Candidates.#4....: 12345678 -> 17656244
HWMon.Dev.#4.....: Temp: 47c Fan: 61% Util:100% Core:2113MHz Mem:4151MHz Bus:16
.