6 x 7990's using ASUS BTC mining motherboard WPA2

[atom]

In this case, (h)ashes per second is the same as keys per second.

4x7990 = 8x7970 ~ 1,12 Mh/s

For a keyspace of 00000000 - 99999999 this means it would take 90 seconds.

Note that the 7990 is a bad one for password cracking. The speed is good but it's constantly overheating.