10-28-2014, 03:59 PM
Literally impossible. WPA kernel in oclHashcat is ~ 14000000 instructions. You haven't posted your clock speed, so I am assuming a stock 1000 Mhz core clock. 2048 cores * 1000000000 Hz / 14000000 instructions =~ 146.3 KH/s max theoretical performance on a 7970 / R9 280X. Most users benchmark real-world performance around 127-135 KH/s.
So what's going on? Well, I think I have a wild theory that also explains why your hack doesn't work when setting FSB speed in the BIOS.
There seems to be a direct correlation between the FSB speed and the system clock. The system clock is calibrated at boot time using the APIC timer, and the local APIC frequency is dependent upon the FSB speed. So accurate timing depends on the FSB frequency. If the FSB changes on a running system, this has a direct impact on timer accuracy, which affects the system clock.
By using a software utility to adjust the FSB speed on a running system, you are literally slowing the clock down. Therefore 50 seconds of running time in your screen shot likely isn't actually 50 seconds, but more like 1m40s. Because of this Hashcat thinks you are doing twice the amount of work you are really doing.
The reason setting it in the BIOS doesn't work is because the system timer is calibrated at boot time, so it is able to compensate for the lower FSB at boot.
So no, you're not really making Hashcat go any faster. You're just making it think it's gone faster by making your system run in slow motion.
So what's going on? Well, I think I have a wild theory that also explains why your hack doesn't work when setting FSB speed in the BIOS.
There seems to be a direct correlation between the FSB speed and the system clock. The system clock is calibrated at boot time using the APIC timer, and the local APIC frequency is dependent upon the FSB speed. So accurate timing depends on the FSB frequency. If the FSB changes on a running system, this has a direct impact on timer accuracy, which affects the system clock.
By using a software utility to adjust the FSB speed on a running system, you are literally slowing the clock down. Therefore 50 seconds of running time in your screen shot likely isn't actually 50 seconds, but more like 1m40s. Because of this Hashcat thinks you are doing twice the amount of work you are really doing.
The reason setting it in the BIOS doesn't work is because the system timer is calibrated at boot time, so it is able to compensate for the lower FSB at boot.
So no, you're not really making Hashcat go any faster. You're just making it think it's gone faster by making your system run in slow motion.