Basis dictionary from diceware is 7776 words and there are 5 words takes from it.

Makes a total combination keyspace of 7776^5 = 28430288029929701376

Since the diceware RNG is hopefully a perfect one we can assume to crack a passphrase on an average at 50% of the keyspace.

So we do 28430288029929701376/2 = 14215144014964850688.

A single (3 year old) hd6990 card runs with 10935 MH/s against a single NTLM hash.

So for a single card, we do 14215144014964850688/10935000000 = 1299967445 seconds.

Then, 1299967445 / 60 = 21666124 minutes.

Then, 21666124 / 60 = 361102 hours.

Then, 361102 / 24 = 15045 days.

Now, if we have 150 cards:

15045 / 150 = 100 days

Some funny theory to continue:

If we'd sacrifice some speed, let's say from 10935 MH/s down to 5042 MH/s per card, we'd able to crack 500,000 of those hashes at once!

But in this case we have to scan the entire keyspace, which is 28430288029929701376.

Makes a runtime of 400 days in total.

But, since we're cracking 500,000 in parallel, we can do:

500,000 / 400 = 1,250 cracked passphrases per day

Makes a total combination keyspace of 7776^5 = 28430288029929701376

Since the diceware RNG is hopefully a perfect one we can assume to crack a passphrase on an average at 50% of the keyspace.

So we do 28430288029929701376/2 = 14215144014964850688.

A single (3 year old) hd6990 card runs with 10935 MH/s against a single NTLM hash.

So for a single card, we do 14215144014964850688/10935000000 = 1299967445 seconds.

Then, 1299967445 / 60 = 21666124 minutes.

Then, 21666124 / 60 = 361102 hours.

Then, 361102 / 24 = 15045 days.

Now, if we have 150 cards:

15045 / 150 = 100 days

Some funny theory to continue:

If we'd sacrifice some speed, let's say from 10935 MH/s down to 5042 MH/s per card, we'd able to crack 500,000 of those hashes at once!

But in this case we have to scan the entire keyspace, which is 28430288029929701376.

Makes a runtime of 400 days in total.

But, since we're cracking 500,000 in parallel, we can do:

500,000 / 400 = 1,250 cracked passphrases per day