05-10-2012, 11:40 AM
Here is why it makes no difference.
A pci-e 1.0 1x lane is capable of 250MB/s transfer.
pci-e 2.0 increased this x2, so 500MB/s transfer.
Since the word lists are broken into segments and loaded into GPU memory, the transfer occurs almost instantly. Even if you have a 50GB wordlist, hashcat will scan it, break it into parts then load those parts as needed. If you have a 3GB card, and load a 3 GB segment, it would theoretically take 6 seconds to load it across all cards. I have not actually tested this myself nor do I know if it would even be possible, but using the lane speeds it should be right.
Bus speed is only a factor when wordlist segments are being loaded since all computation is done on the GPU. This includes rule generation, brute force masks, etc. The only thing that you could do to speed up the start time is use an SSD for your wordlist storage, but you will not see a speed increase in recovery speed.
A pci-e 1.0 1x lane is capable of 250MB/s transfer.
pci-e 2.0 increased this x2, so 500MB/s transfer.
Since the word lists are broken into segments and loaded into GPU memory, the transfer occurs almost instantly. Even if you have a 50GB wordlist, hashcat will scan it, break it into parts then load those parts as needed. If you have a 3GB card, and load a 3 GB segment, it would theoretically take 6 seconds to load it across all cards. I have not actually tested this myself nor do I know if it would even be possible, but using the lane speeds it should be right.
Bus speed is only a factor when wordlist segments are being loaded since all computation is done on the GPU. This includes rule generation, brute force masks, etc. The only thing that you could do to speed up the start time is use an SSD for your wordlist storage, but you will not see a speed increase in recovery speed.