Brutforce too slow?

Hello everyone,

bruteforcing with the 7970 and only ?d seems a bit slow here.

oclHashcat64.exe --gpu-accel=32 --gpu-loops=32 --gpu-temp-abort=90 -m 2500 -a 3 -i --increment-min=8 --increment-max=9 -1 ?d -2 ?d -3 ?d -4 ?d test.hccap

Gives me:
Input.Mode: Mask (?1?2?2?2?2?2?2?3) [8]
Time.Estimated: 1 year, 135 days
Speed.GPU.#1: 129.0 kH/s
HWMon.GPU.#1: 92% Util, 68c Temp, 67% Fan

I have defined -1 to -4 since the generated mask used -1, -2 and -3 even when I only defined -1.
Since haschat should try 00000000 to 999999999, the estimated duration seems a little long for me.

Where is my mistake?
Thanks in advance