The speed varies between 1300 KH / s and 608 KH / s

[Tuxel]

Hello I have question about the speed.
The speed varies between 1300 KH / s and 608 KH / s.
Where does it come from?

greetings
Tuxel
Sorry for my bad English

Session..........: hashcat
Status...........: Running
Hash.Type........: WPA/WPA2
Hash.Target......: /home/schmidt/hashcat-3.20/hash.liste
Time.Started.....: Thu Dec 29 12:44:45 2016 (6 mins, 42 secs)
Time.Estimated...: Sat Feb 29 22:38:07 2020 (389418 years, 298 days)
Input.Mask.......: ?1?1?1?1?1?1?1?1?1?1?1?1?1?1?1?1 [16]
Input.Charset....: -1 ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789, -2 Undefined, -3 Undefined, -4 Undefined
Input.Queue......: 1/1 (100.00%)
Speed.Dev.#1.....:   929.7 kH/s (394.80ms)
Speed.Dev.#2.....:   443.2 kH/s (268.08ms)
Speed.Dev.#*.....:  1372.9 kH/s
Recovered........: 0/35 (0.00%) Digests, 0/35 (0.00%) Salts
Progress.........: 399245312/16871200686279229440 (0.00%)
Rejected.........: 0/399245312 (0.00%)
Restore.Point....: 0/452598034045687125 (0.00%)
Candidates.#1....: T234567898888989 -> TFLE777898888989
Candidates.#2....: DV03VANANANANANA -> DTYU120123456611
HWMon.Dev.#1.....: Temp: 47c Fan:  0% Util:100% Core:1873Mhz Mem:4513Mhz Lanes:16
HWMon.Dev.#2.....: Temp: 36c Fan:  0% Util:100% Core:1455Mhz Mem:3004Mhz Lanes:16


Session..........: hashcat
Status...........: Running
Hash.Type........: WPA/WPA2
Hash.Target......: /home/schmidt/hashcat-3.20/hash.liste
Time.Started.....: Thu Dec 29 12:44:45 2016 (18 mins, 8 secs)
Time.Estimated...: Sat Feb 29 22:49:33 2020 (876509 years, 279 days)
Input.Mask.......: ?1?1?1?1?1?1?1?1?1?1?1?1?1?1?1?1 [16]
Input.Charset....: -1 ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789, -2 Undefined, -3 Undefined, -4 Undefined
Input.Queue......: 1/1 (100.00%)
Speed.Dev.#1.....:   413.0 kH/s (394.74ms)
Speed.Dev.#2.....:   197.0 kH/s (271.21ms)
Speed.Dev.#*.....:   609.9 kH/s
Recovered........: 0/35 (0.00%) Digests, 0/35 (0.00%) Salts
Progress.........: 817823744/16871200686279229440 (0.00%)
Rejected.........: 0/817823744 (0.00%)
Restore.Point....: 0/452598034045687125 (0.00%)
Candidates.#1....: T234567898888989 -> TFLE777898888989
Candidates.#2....: XV03VANANANANANA -> XTYU120123456611
HWMon.Dev.#1.....: Temp: 47c Fan:  0% Util:100% Core:1885Mhz Mem:4513Mhz Lanes:16
HWMon.Dev.#2.....: Temp: 36c Fan:  0% Util:100% Core:1455Mhz Mem:3004Mhz Lanes:16

[atom]

Maybe the large keyspace. Try something more normal like ?l?l?l?l?l?l?l?l and report if it still occurs