hashcat-3.10 slower then cudaHashcat-2.01

I replaced cudaHashcat-2.01 by hashcat-3.10 and the speed of cracking WPA2 is slower.

cudaHashcat-2.01:
Device #1: GeForce GTX 560 Ti, 1024MB, 1800Mhz, 8MCU
Speed.GPU.#1.:    38269 H/s

hashcat-3.10:
Device #1: GeForce GTX 560 Ti, 256/1024 MB allocatable, 8MCU
Speed.Dev.#1.:    26930 H/s (95.12ms)

Why is the speed slower ? 

Thank you.

TOM